Some things don't need explaining. Hell, Capt Marvel has been in space for 20 years and not aged... they didn't even bother to explain it. However, the way I'd bring X-Men & F4 int the fold:
F4 - same space exploration/cosmic rays, only they were lost in space (X amount of years) some type of void, and the Snap gets them out of the void, back into the solar system to make their way home. But they already have their powers, possibly even Franklin and/or Valeria.
X-Men - keep their entire backstory in tact, and use part of the House of M/Five Lights storyline. And Magneto just physically ages slower. The X-Men are the proper adult ages, mutants have always existed, but since there were very few of them (lets say under 2000) in the world, aside from average random prejudice acts, they were on a smaller scale, so were monitored but not important. Some 10 or so years go, Jean Grey made the sacrifice and absorbed the Phoenix Force, carrying it into space, to save the world which very few knew about. The Snap breaks the Phoenix Force free from Jean, causing the Five Lights storyline...first mutant born, and new mutant powers activated around the world...causing global panic about the world's now unpredictable "Mutant problem." It's especially a problem when people realize that Mutants were born that way. Considered a disease, abomination, abnora, freaks....that brings you into the current climate of "I can't believe prejudice still exists like that today"" argument, that some of us still experience today.
F4 - same space exploration/cosmic rays, only they were lost in space (X amount of years) some type of void, and the Snap gets them out of the void, back into the solar system to make their way home. But they already have their powers, possibly even Franklin and/or Valeria.
X-Men - keep their entire backstory in tact, and use part of the House of M/Five Lights storyline. And Magneto just physically ages slower. The X-Men are the proper adult ages, mutants have always existed, but since there were very few of them (lets say under 2000) in the world, aside from average random prejudice acts, they were on a smaller scale, so were monitored but not important. Some 10 or so years go, Jean Grey made the sacrifice and absorbed the Phoenix Force, carrying it into space, to save the world which very few knew about. The Snap breaks the Phoenix Force free from Jean, causing the Five Lights storyline...first mutant born, and new mutant powers activated around the world...causing global panic about the world's now unpredictable "Mutant problem." It's especially a problem when people realize that Mutants were born that way. Considered a disease, abomination, abnora, freaks....that brings you into the current climate of "I can't believe prejudice still exists like that today"" argument, that some of us still experience today.
)so there's one idea you can recycle
