Day 3 of full on use, and well over a week since a gameinput crash. Deleting all of the Xbox bits seems to be the way.
But yes, kind of a stitch up as regards gamepass. For what it's worth, I've found that as long as you have a desktop shortcut to a game which you've downloaded through gamepass, the game will still work after Xbox app, gameservices etc has been deleted... assuming you haven't uninstalled the game too, of course! Bizarrely, uninstalling the Xbox app doesn't uninstall the game, it just sits there on your hard drive...