Autopilot fighting for control

In simulation, if I set the autopilot to maintain the altitude, and
then try to change pitch with the controls, the control surfaces
barely move, and I can hardly have any effect on pitch.

I think this is a limitation of the simulator. My guess is that, in
real life, the autopilot continuously adjusts trim, and so, if you try
to change pitch with the yoke, the A/P retrims to cancel out your
efforts, and the net effect is that you can change pitch, but you must
exert very high control pressures to do it (in order to overcome the
trim that the A/P is applying to neutralize your efforts).

Is this correct? I can see why this is difficult to simulate with
controls that don't provide feedback, but I want to make sure that I
understand the difference between the sim's way of doing it and the
real thing.

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