honestly as much as i enjoyed the xmen films, its going to be impossible to juggle all that shit and give everyone meaningful screentime, thats always the problem with the X-men films, and why by the 3rd one the screen time for everyone was cut to a handful of minutes. there's like 151 mutants people all love and have great powers how you going to fit that all in a 2 hr movie or even 3 of them a year?
Original cartoon and first X-Men movie managed their introduction not badly, tbh. Both had the same premise: young mutant (Jubilee/Rogue) just got their powers and unintentionally cause damage (broke electronics at home/put bf in coma). They get chased and later rescued by a "team" with powers (both had Scott and Storm) and taken to the mansion for the proper introduction (War Room/Med. Room) of who and what the X-Men are. Both had also a small scene with exposition of why they have powers, making a difference with other heroes about how they are born this way.
If you never heard of the x-men before, this is enough to give you enough context: Xavier is the founder, Cyclops is the leader, Jean can read minds, the Mansion is their HQ, etc. The cartoon fleshed them all a little bit more: Beast is the brains of the group, Morph was the prankster, Gambit was the ladies' man, Logan was... Logan. All in 40 minutes, the run of Night of the Sentinels.
As they keep claiming it will be the "Mutant Saga", I take it as we're having origin stories of the original group, which is Scott, Jean, Bobby, Beast, and Angel. There is no way they're gonna adapt all the mess that it was the split of two groups in the 70s, so I take they will just find a way to later add the other popular mutants (remember they said there is already a casting call for Kitty and Gambit, and they came in the 80s-90s respectively). As there were also rumors of Sinister being cast, there is the chance to also have an origin for Scott.
It's really not impossible to adapt the X-Men saga, but Disney currently are too ambitious and they want all stories without the building. If it depended on me, I'd make the first movie about the original five members vs Magneto and the brotherhood, which includes origin stories for the five students, the backstory for the
romance friendship between Xavier and Magneto, and the possible recruitment of new less known mutants like Polaris, and Havok, which are just small roles. But people are also impatient and they will demand for Logan, Gambit, and Storm, and Disney, being idiots, will comply and we might end up with another Eternals fiasco.