If you’d rather play with a gamepad: there are two ways to resolve the gamepad/headtracking conflict, which occurs whenever a game can‘t handle simultaneous mouse (emulated for tracking) and gamepad input.
You can either switch on the ‚X-Box Gampad Override‘ option, which actually is a fullblown, fully configurable gamepad > mouse/keyboard mapping tool. With some luck only overriding the offending axis (‚Partial’) is enough, but more likely it will be necessary to map the axes as well as the buttons (‚Full‘).
Alternatively you can resolve the conflict by making head tracking emulate a gamepad instead of the default mouse emulation. That‘s fairly laggy since games typically apply heavy filtering to gamepad input, so it’s not really well suited for FullVR, but it can be good enough in immersive screen/cinema mode.