I've been thinking that it might be a good idea to keep the X-Men and other mutants separate from the MCU.
I made another post that included some reasoning for some possible benefits of this in another thread. I'll mention some reasoning for what some more benefits may be below.
A benefit from keeping them separate at least for some number of live action movies and live action tv/streaming shows is that maybe all or most future live action tv/streaming shows with Marvel characters could involve mutants and take place in a mutant universe separate from the MCU universe. A benefit of this is that due to the mutant concept, it maybe makes it easier to create new super powered people than it does in the MCU. So if live action tv/streaming shows are mostly made about mutants, it saves more non-mutant characters' first appearance in the MCU for movies rather than having them appear in live action tv/streaming shows. Like I said it might be easier to come up with new characters that can appear in comics and then future live action tv/streaming shows or movies with the mutant idea than a MCU without mutants. New superpowered mutant characters could even be made up for a live action tv/streaming show or a movie without first appearing in the comics if desired and there would be an easy explanation for their powers. However people might not be that excited to see newly made up characters in a movie or tv/streaming show as they might be compared to an older character that's already popular from what has happened with them in past comic books and cartoons.
I want to mention some more benefits related to having separate universes below after I mention some comments I have about non-mutants in a mutant universe, past MCU tv shows, and ideas I've had about the potential connectivity between tv/streaming shows and movies for a separate mutant universe and a separate MCU universe as I think this thread is a good place to mention those things. Someone reading this could scroll past this part down to the more benefits and read this part afterwards if they wanted.
There are only so many already somewhat popular characters from Marvel comics that aren't mutants that haven't already appeared in a MCU movie or tv/streaming show. So, saving these non-mutants often for movies might be a better thing to do than what has been done so far. Although, a small number of people in the mutant universe who are heroes that don't have superpowers or could get their superpowers from something besides the 'x-gene' if it would be desired for whatever reasons. I think it might be a good idea to not use non-mutant characters that are popular in the comics in this mutant universe however. Maybe they could make up new non-mutant heroes and/or villains that never appeared in comics, but like I said it's probably easier to come up with reasoning for the powers of a character by them having the 'x-gene'.
The MCU could change the past of the Marvel tv/streaming shows that are said to be currently in the MCU current 'timeline' so far with time travel. Marvel could make a movie that involves time travel and say that some things involving those tv/streaming characters happened differently due to some things changing in the past before the time periods of those shows. They could then make some new movies with characters that have appeared previously in MCU tv/streaming shows and those new movies would have things happen somewhat differently with these characters that appeared in those past MCU shows. Having them already previously appear in a tv/streaming show helps some people have greater familiarity with the characters and maybe be more excited for them to be in a movie, but people making the movie would have to deal with certain expectations there may be on the movie due to people's familiarity with the tv/streaming show which can have some drawbacks.
I guess some fans of the tv/streaming shows might get mad if these time travel changes happen, but it still might be worth doing. Some things like this have happened in comic books in the past with time travel. Maybe they could wait several years before making movies which show how things changed for these characters due to time travel. Some of these characters in the tv/streaming shows like the Defenders, the Inhumans, and the New Warriors have some decent potential for movies I think and some decent popularity and history just from their appearances in the comics. So, it seems like maybe not as good of a use of their potential with some of these shows especially for the Inhumans. However, maybe Marvel doesn't care that much about using characters that have some popularity due to their appearances in comics and/or cartoons prior to being in a movie given that a character played by Tessa Thompson in Thor: Ragnarok doesn't seem to be based on a specific named character from the comics, but rather from a group of characters in the comic.
I'm not sure how much input actually the people behind the MCU tv/streaming shows would or should have on mutant universe tv/streaming shows. It seems like what they do in the recent MCU shows doesn't have that much effect on what the MCU movies do. It seems like what the recent MCU movies do has more effect on what the MCU shows do. I think the creators of the movies and live action shows may have at some point stopped collaborating as much as they may have done initially for whatever reasons. I think the split of Marvel Studios from the rest of Marvel may be related to this drift in collaboration.
Maybe the people behind the MCU movies might prefer Jeff Loeb and whoever else is involved heavily in the MCU shows to stop making shows that are supposed to be set in the current MCU and instead make shows that would be set in a separate mutant universe. If they wanted they could have the movies and shows set in a mutant universe have greater connectivity with each other than the recent MCU movies and shows seem to have recently had. I guess it might depend somewhat on what people making the recent MCU movies want to do and how they would want to be involved with future movies and shows set in one or both theoretical separate movie/show universes. If there really was some sort conflict between Marvel Studios and people involved with Marvel shows, perhaps they might want there to still be a similar degree of connectivity between movies and shows set in a mutant universe as the amount of connectivity between shows and movies recently in the MCU (this again would be maybe dependent on how much involved Marvel Studios people would plan to be in movies set in a separate mutant universe.)
However, maybe they might allow greater connectivity for whatever reasons. (Disney might want more superhero tv/streaming shows that many people think are very important relative to superhero some movies. Also, a desire for greater connectivity may be influenced by whether Disney thought it might improve tv rating and/or viewings on streaming services.) The fact that previous X-Men movies have already done time traveling and changing the history of things in the timeline for the movies might mean that Marvel Studios might allow the tv/streaming shows people to have more influence and importance and maybe do more experimental things with their connections to movies in a mutant universe. I think because people already have experience with timeline changing for the X-Men movies, people might be more willing to accept a timeline change in a theoretical mutant universe. So, because I think people might more readily accept a timeline change, I think Marvel Studios might be more willing to let the shows have more influence on the movies because Marvel Studios might be more willing to change a theoretical mutant universe timeline due to being unhappy with how some stuff in tv/streaming shows turned out.
Perhaps part of Marvel Studios allowing the shows to be more experimental could involve allowing shows that are not appropriate for children to have significant influence on the movies. Of course, I guess it would depend on what exactly people in charge want to do with movies and shows about mutants and possibly the group of things associated with the names Fox or FX (or whatever business names they associate with shows and movies currently associated with the names Fox or FX). This depends on whether they want future movies associated with mutants (and maybe past movies associated with mutants) to continue to be associated with businesses featuring the names Fox or FX or new names to replace the names Fox or FX. They might have some kind of associations of types and styles (in regards to child-appropriateness, humor, cinematography, and other things) of shows and movies that they want to associate with those names Fox and FX. Or maybe they don't plan on having some kind of particular association in regards to 'style' of shows and movies associated with those. I also guess the appearances of certain characters in certain movies and the idea of separate movie/show universes might depend on ideas Disney/Marvel is having about what to do in theme parks with movies/shows with Marvel characters and for specific groups or the large majority of movies/shows associated with Fox and FX. Anyways, perhaps that's a bit of a tangent, but I talked more about similar things in the post I linked at the beginning of this post.
Now back to some more possible benefits of separate universes I've been thinking about.
Having a separate mutant universe from the MCU could make it easier for viewers to eventually accept future movies and/or shows featuring separate universes with alternate versions of the same characters that appear in the one universe. I think something featuring a cross-over of alternate versions of characters from alternate universes recently happened on the DC tv shows called 'Crisis on Infinite Earths'. A benefit of getting people to accept the idea of alternate versions of characters in separate universes is that it can allow people who like one version of a character to see more stories about a somewhat similar alternate version of a character. Additionally, Marvel could maybe eventually do a cross-over like that with alternate version of characters through methods that have occurred in comics. Various kinds of cross-overs with characters (and sometimes objects) more associated with one series of comics books than a different series of comic books have tended to be popular in comic books and make more money than regular comics. Some people have even criticized Marvel for doing too many cross-over comic books, but the reason they likely have increased the amount of cross-over time is that they tend to make more money for Marvel than regular comics at least over a short period of time per comic book.
I think keeping a mutant universe separate from the current MCU could have a benefit if the universes eventually did crossover somehow in the future. I think there might be greater excitement and probably greater money made for Marvel for movies and maybe tv/streaming shows if separate universes were maintained for a time with people behind the creation of the MCU movies and possibly MCU tv/streaming shows having significant input on the mutant universe movies and possibly mutant universe shows as well. Eventually after some time has passed, characters from the two universes could appear in the same movie for some reason and then possibly go back to their separate universes for at least for some period of time. They could then later have another movie or series of movies where characters from the two movies appear in one or more more of the same movies and then the characters largely stay in movies set in separate universes again for some period of time. This could possibly keep occurring repeatedly with people being excited for it to some degree if it is done carefully I think. Although, maybe a small number of characters that were born in one universe could appear in movies set in a different universe from the one they were born during these periods of time where many characters from the two universes largely don't appear in the same movies. I think the increased interest and financial benefit of movies and possibly shows due to the X-Men (and other mutants) appearing in the same universe as characters already in the current MCU would die down if they are just introduced and then routinely appear in the movies and possibly shows after their introduction.
Due to how important and numerous mutants seem to have tended to be in the world of their past movies, I think it might be difficult to keep from mentioning mutants in movies and shows that are trying to be focused on non-mutant characters and to keep from mentioning non-mutant super powered characters in (basically X-Men, Deadpool, X-Force, etc.) movies trying to be focused on mutant characters. This could cause some issues with managing the reasoning for why certain characters aren't appearing to deal with some threat in a movie while other characters are appearing. Marvel might want certain characters to only rarely or never tend to appear in certain movies with certain other characters as the characters under consideration might tend to appeal to different people, they might have certain similarities to other characters (such as in their powers), certain characters might have certain powers that they don't want to appear in certain movies (for reasons such as it might make a fight much less interesting), Marvel might not want to associate certain characters with certain other characters in a 'cross-over' movie' due to a difference in the style of the movies some of the character(s) tend to appear in (such as with Deadpool), and for some other reasons.
Additionally, having these separate universes means that Marvel could be able to more frequently have team-up movies and/or movies with drastic threats to beings in a universe without people getting as tired or as accustomed to the big movies as they might if movies like that came out more frequently than now but all set in the MCU. For instance, Marvel could have a big team up movie involving many characters in one universe come out once every year which they haven't done so far, but they could alternate which universe the team-up movie takes place. In one year it could be in a mutant universe movie and in the next year in a MCU movie. I don't know if it would be a good idea to release them that frequently, but that's just an example of what they could do. A team-up movie in a mutant universe could really be multiple teams combining in one movie; such as X-Men joining forces with X-Force or something like that. Perhaps having a tendency for different 'styles' for the movies in the different universes could help decrease people getting accustomed and losing excitement for big-team up movies if they did something like that alternating years schedule I mentioned. However, possibly I could be wrong about the separate universes helping with a decrease in excitement.
A different benefit to having the different universes is that it could allow Marvel to slow down the pace at which they have been recently writing and making MCU movies while ultimately still keeping up the same pace as before in some sense, but having the mutant universe movies making up for the decrease in pace of MCU movies being released. This could maybe allow writers and directors more time to think about future movies they are thinking of making. That is dependent on how the structure when pre-production of movies begins and how many writers and directors they have working on different movies. Also, this could potentially allow Marvel to make movies about certain superheroes and big over-arching villains (like Thanos and Loki) over a longer period of time than they have so far. For example, possibly Marvel could make movies about characters that are like 20 years old and have a similarly aged actor in their first movie and continue making movies with this character and possibly the same actor over the next 25 years if they wanted. This would mean that they could have a group like the Young Avengers or Ms. Marvel and not run out of ideas for movies featuring them or want to kill or retire the character as quickly as they seem to have recently by spreading out when the movies come out. However this might depend on how quickly they want the characters to age in the movies.
It seems like so far the MCU movies have had the passage of time in the movie universe be similar to the passage of time in the real world. If they wanted to continue this rate of the passage of time, they could have some things that happen between the appearance of some characters in the movie not be mentioned explicitly in some movies (like how Star Wars skipped over some periods of time that some Star Wars books are set in). They could have the character age at rate similar to the real world like the actor portraying them and then maybe go back later and make movies or shows that are set during these period of times that were skipped . They might have to use cgi somehow to do that however. The characters in the movies/shows that take place during those skipped periods of time could age at a slower rate of time compared to the passage of time for the release of their movies/shows in the real world. This could be more easily done if cgi is used for the character, but they could also just recast the character with a different actor for this skipped period of time and release the movies like I said over a longer period of time than the period of time covered in the movies. For instance, the release of a series of movies that covers what happens to a character over a skipped period of time could take 5 years for all of the movies to be released even though the period of time within the MCU might be much less than 5 years for events to occur during this series of movies that are set during a previously skipped period of time.
He had two infinity stones, he easily defeated Cap, and tricked all the Avengers to getting him on the Helicarrier to release the Hulk. 
(though it will be tough to avoid images and thumbnails for it so I'll probably end up seeing the Trailer 2, but try hard to avoid clips/tv spots/etc)