I'm pretty much the same fwiw I currently use stage manager and double click the top bar of the window to maximize (that's different than the green button)

don't you just love how many ways of going full screen there are in macOS

Maximizing and Fullscreening are different modes in all operating systems.

I use Niri and it has 3:

1. Use all width (windows are full height by default) and display system bar

2. Use the entire screen and hide the system bar

3. Same as 1 but make the app believe that it’s in Mode 2

Give flashspace a try.