Okay, hear me out on this one:

While the Fox movies never ended up part of the MCU, and the X-Men in general joined the MCU only very recently, there is very explicit mention of the X-Men in an early post-credit scene. This implies to me that Disney, at the very least, considered to integrate the Fox movies into the MCU.

Of course, Kitty Pryde was played by, at the time, Elliot Page in the third movie, who later reprised the role in Days of Future Past. Had these movies become part of the MCU, the role might very well have continued to be around for a lot longer.

Thing is, Elliot Page, as you might have figured out from the name, came out as trans a few years back, which is the reason why his character in Umbrella Academy is also a trans guy. Now, this puts Marvel into an interesting spot: Write the character out of the MCU entirely? Recast the role of Kitty Pryde? Or use this as an excuse to make her trans to keep Elliot Page around? (I know, realistically, they would not have done the latter, because then the movies wouldn't sell as well because everyone would start complaining that Marvel has "gone woke", but i do like the idea this happened in at least one alternate universe)