Depends very much on the aircraft. I find the Carenado Cessna Skymaster II is almost flawless when being directed by A.I. Pilot in MSFS 2020. Literally completes 98% of its flights end-to-end (including ‘hands-free’ take-off and landings, and taxi-to-park) without any issues.
Other planes, not so much (if at all). Something Carenado did with Skymaster II sets it well apart from the rest. I have no idea what that might be, but this plane plays extremely well with A.I. Pilot - and in so doing shows exactly what A.I. Pilot could (and should) have been to the wider sim.
To be certain of what I am saying, I completed a short 75-mile flight this morning in MSFS 2020 with the Carenado Skymaster II. ‘Hands-off’ from the runway (simply toggled the plane into ‘A.I. Pilot’ mode) - and the entire flight was completed 100% trouble-free.
Why A.I. Pilot is missing from 2024 is a mystery - and a massive blow. It clearly did work, given something about particular airplanes and how they are set-up by their devs.