The on/off throttle behaviour, from previous posts i’ve seen, can be caused by mapping the physical throttle axes to the wrong axis command. Not at my sim PC at the moment, but the correct axis command does NOT have “(0-100%)” in its name, so something like “Throttle Axis 1”.
Also, as suggested above, IIRC, there are also axis commands that control all of the virtual axis levers at once, so check that you don’t have that mapped to one or both of your warthog levers, as well as having the throttle 1 and throttle 2 virtual lever axis commands mapped, especially if any of the mappings is a “(0-100%)” variant.