True, but I think if they’re going to continue to use the MCU as the jumping off point then they’ll likely use specific stories that aren’t tied to a specific movie story-arc. Basically think of the Marvel Theme Park Universe (MTPU), actual Disney term, as separate but inspired directly by the MCU.
Yes I think this is the way they are going as well! They are part of the MCU but their story lines are basically in an alternate universe so they can shape the stories anyway they want from the films. And I love the idea of a MPTU and remembered Fresh Baked made a video about this a year or two ago. But I liked his idea too and that was that the rides themselves would not only take on another life but they could start connecting them as more are built. Nothing grand, just more subtle things like maybe you would see a picture of Tony Stark defeating a Hydra robot in Hong Kong in the Spider Man queue in DCA or the GOTG rides in DCA and Epcot may reference each of those adventures.
Disney is all about cross promotion and while they have done minor ride crossovers in the past its pretty minimum given so many are in different locations and eras. But MCU all takes place in the same era and naturally the characters (now) pretty much know each other. So they could build story lines connecting all the Marvel attractions together worldwide.
And they've already done that with Star Wars now that Star Tours ends in Galaxy Edge and I won't be shocked Star Tours is represented in that land somewhere. So imagine what it could be like when Marvel is fully up and running.