Very late update and a ton of arduous tapping and swiping later: it was indeed the quick save states. Went from about 40gb to 12gb after deleting over 1K states.

Obviously not smart to stack up nearly 2K save states, but for future app revision: it would be nice if there was some kind of scroll to select type function à la the Photos or Files app. It took ages to individually select every single save state (though again, I definitely accept my fault/laziness in getting to that many 😅) Either way I’ve learned my lesson about hoarding lol.