To circle back to FF7 Rebirth, I really don't think it'd be impossible to bring to a Switch successor, technically at least.
Given it's at near 4K in graphics mode and above 1080p even in performance mode on PS5, I'd imagine that a 30fps port could be done with some judicious trimming of settings, similar to what we saw with games like Dragon Quest 11 or Witcher 3 or Dying Light on the current Switch.
That would certainly be one way for them to squeeze some more money out of it, provided whatever deals they have in place allow for it to be ported elsewhere of course.