> when an airplane is close to the ground it can have significantly higher AoAs without stalling

No. A wing will stall at a consistent critical angle of attack. Ground effect works by increasing the lift available for a given angle of attack, not by allowing a larger angle of attack to develop.

Parent comment was asking about the need for minimum airspeed to set the AoA sensors into a reliable state such that they could be checked at the gate, though, which is unrelated to ground effect.

Not necessarily at the gate, but possibly during taxi and definitely during the takeoff roll (ideally before V_1).

Granted, btw, that AoA readings on the ground may be unreliable - the question remains whether AoA disagree could be detected reliably before takeoff.

If the issue you're worried about is only MCAS related, it seems like the takeoff roll might be a poor place to want to detect it.

An abort just prior to V1 is a no-joke exercise from a safety standpoint. MCAS operation is suppressed with any flaps deployed, so taking an airplane with a failed AoA sensor into the air and troubleshooting/returning to the departure airport if needed or simply flying with an INOP MCAS may very well be safer than a high-speed abort.

Good point. Instead of aborting take-off, either do a circuit back WITHOUT retracting flaps, or set Stab Trim switch to CUTOUT and fly to destination trimming manually with the trim wheel? Wonder what pilots are briefed to do currently (well, if MAXes were flying).