A lot of Samsung users I know really loved the hide nav bar button from android 8.0. I myself liked it too. Is it possible you can bring back that old feature? A lot of average users find the gestures complicated and annoying. Having the nav bar that you can hide and bring back by swiping up from the bottom was a really good idea and it would be nice to see that return rather than having the nav bar toggle in the quick menu.
UX concept has been changed to use gestures. It's not very probable that it would be change. You suggestion might be considered if there will be a lot of support for this post from other users (positive comments and likes)