So when you use gesture based navigation you have a white bar on the bottom of the screen along with a black bar.
Is it possible to only have the white bar so apps will go to the bottom of the screen instead of being cut off by a black bar
This is stock android behaviour and ASUS follows pixel like experince with ZENUI I. E. Close to stock experince. So for now it cannot be adjusted. but you never know if ASUS receives numerous requests for same UI than hopefully it may be adjusted in near future. Or may be if Google make few adjustments too, than definetly ASUS will adopt it.