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.
Gestures are faster and more intuitive. You don’t have to do hand gymnastics just to get to the recents apps screen or to go back. The gesture bar can be hidden and it will still work, unlike the buttons which you have to swipe up to bring back, and even when shown it doesn’t take up much screen real estate. Apple got it right when they brought gestures to the iPhone and I’m glad Google copied.