I've only got Android to test on, sorry! When exiting full screen on android I get this "Restore App" button, does this exist for you?
It MIGHT be an itch problem otherwise 🤔
This is all I see on iOS, nothing else I can see. It still runs non-windowed but is a little harder to use in this state.
Notably, this only occurs on iPadOS, not on my phone. On phone iOS I can't even exit fullscreen and it stays maximized no matter what.