I’ve just tried shifting the reference_datum_position to negative wing_pos_apex_lon in my case changing the reference datum to -22.87 and the aircraft now has much better pitch control comparable with FSX, but with all the values from .air and cfg transposed to the new flight model format.
The only thing is the elevator authority only seems to work after being airborne - from the ground I can’t get the nose wheel up at takeoff speed or above, but once airborne it’s normal…! Jet engines also have the right values as far as I can see, but also not enough power on take-off.