XR Controllers have the joysticks mapped as Vector2Control rather than StickControl. This means that they can't be mapped as individual 1D axes, and you can't map up,down,left,right as buttons.
Ideally they should either be remapped, or everything in StickControl should be moved into Vector2Control (I can't think of a reason not to expose those values for all Vector2 input). StickControl could be left in as an empty class for compatibility.