Honestly, I see similar to the rumors--a standalone Mutants film that doesn't have any established connection to the X-Men or Mysterio. I see it focusing on Wanda after Multiverse of Madness, trying to recover from whatever happens with the Scarlett Witch and finding out that because of her actions; the entire world has shifted due to the creation of Mutants.
Deadpool 3 should also help fill the gap too, especially if they use that as a starting point for Wolverine.
This would be something that'd likely be filed and settled since 2018, when Endgame was in production. I'm honestly not too sure that Scott's daughter will even be apart of Young Avengers. Considering they already got a varied lineup for the next wave of Avengers with Young Avengers.