we have tested R6 on Xbox One many times since your first report,
no similar problem found.
please do not think you are using a stick, you are using a mouse for aiming by Cross Hair's translation.
and we have mapped the mouse's movement to stick movement with the deadzone in consideration.
if your deadzone=5, and the input=6, the game will give you a MIN speed.
if your deadzone=10, and the input=11, the game will also give you the same MIN speed.
so whatever your choice is, you will gain all the necessary speeds from MIN to MAX,
and all these speeds(from MIN to MAX) are controlled by the movement of your mouse, not a stick.
the MIN mouse speed will correspond to the MIN game speed.
we do suggest you should restore all the settings to their defaults,
and change them according to our instructions.
and one more thing, you could try setting your mouse DPI to 6000, and set HIP/ADS=20,
some mouse can not maintain the highest performance continously.
or you can shot a video and send it to support (at) reasnow . com
to show us your trouble.