Use the defaults.
Rule of thumb
Use 360 Distance to preserve the rotational distance (good for movement).
Use Monitor Distance - Vertical/Horizontal 0% to preserve the mouse sensitivity (good for aiming).
I found a work-around!
Just changed my "GstInput.DylanOption_MouseFlightSensitivity" and "GstInput.DylanOption_MouseSwimSensitivity" to the same sens as my "GstInput.MouseAimSensitivity" and I was able to fly and swim normally again.