Rest of the things, it’s absolutely no sense when the app gives different options on different android versions and worse and more limited options on NEWER versions.
But apart from that, the way you said NORMAL ANDROID BEHAVIOUR?
Suppose there’s an app
I went to app menu like
Home, A, B, C
All have sub menus like A1, A2, A3, B1, B2, B3, C1, C2 and C3
Now what is normal Android behaviour?
Press BACK>reach home>press BACK>exit the app.
But no! For you now the normal Android behaviour is to press BACK 11 times and you’ll be taken to each menu/sub menu you visited in the app in the process before coming back to the Home menu finally and then one extra tap at BACK.
I’ve never seen such a stubbornness from any app devs. If you’re not a dev then that’s a different story, but if you are, you need to learn maturity.