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.
I was on Lollipop and had root, I had next and previous music buttons on either side, good times