From Deadline...
Sources close to both [sic] the project say more than 60 MCU characters could reprise their roles, including everyone from Mark Ruffalo, Chris Hemsworth and Benedict Cumberbatch to Tom Hiddleston, Simu Liu and Karen Gillian. Unlike the first four films in which there was a core group that consisted of Robert Downey Jr., Chris Evans, Scarlett Johansson, Hemsworth and Ruffalo, many of the characters in this film would have equal footing, making it more of an ensemble feature instead of a handful of characters leading the team.
"Sources"
"could"
"both" (both what?)
Even with two part 3-hours-each movies, that's just six minutes of focus on each hero. We're not even up to 60 hero leads counting even the TV shows, let alone "more than 60."