I guess this has been said before but I want to reiterate it here.
The 3 button navigation is simpler, much faster than gestures and less prone to input errors than gessure navigation.
It’s easier to use the phone one handed when using 3 buttons especially considering the size of phones nowadays.
The only real downside to the 3 button bar is the space it takes away from the screen. I can’t deny you get better immersion due increased screen size and gestures being intuitive (for me at least.
With that said I understand that depending on the brand the feel of gestures and their quality can vary (like between a pixel phone and a xiaomi device), but in terms of efficiency (and maybe slightly improved battery life due to less animations) and simplicity the 3 button navigation is still miles ahead.
Issue is that developers are honestly, kinda of dumb in regards to the menu gesture, and AFAIK there wasn’t an actual “canonical” guideline for that gesture in the first place.
Discord offers the best implemention in my opinion, as it can function on the middle of the screen and not on the edge, so it doesn’t interfere with system gestures.