Is it too late to retool this movie for the MCU?
That line "
Last question... Do you know what mutants are?" in the trailer opens up a world of possibilities. They could hold it off for a few months, reshoot the ending and remove all Foxverse references and make this the intro to the CONCEPT mutants as something to be feared, before the inevitable X-Men movie becomes our intro to Xavier's actual team. Then have then both converge eventually once Xavier begin searching out mutants for his school in a later film.
If this entire film is isolated in an asylum, then that'd be the way to go, IMO. But that of course means they'll never do it.