What are plausible X-Men integration theories for the MCU timeline amid multiverse?

[EmmaRT]

I just rewatched the entire Infinity Saga and I'm deep into some MCU theories about the future, specifically regarding the multiverse and the introduction of mutants. There's a lot of speculation that the upcoming Fantastic Four movie might be set in an alternate universe, which could be a way to soft-reboot certain characters. What are the most plausible theories you've heard about how they'll integrate the X-Men into the main timeline, and do you think the multiverse arc is setting up a new overarching villain like Kang or something even bigger like the Beyonder?