Ever since its appearance in Android Pie, I always consider 2 button navigation is a bad attempt by Google trying to play catch-up with the fad generated by the iPhone X. However, due to a bug with A13 QPR2 it had to be temporarily removed and many were not happy about this. So, 2 button navigation users, may I ask why do you prefer this method? To me it makes you do more for the same action whilst doesn’t save any screen space.
Dedicated buttons for copy, paste, and undo would be amazing. I don’t think Android has good support for undo though, it would be cool to undo accidental swipes like when you accidentally swipe away a notification, or if you accidentally tap the space around a dialog box and it disappears