I'm an airworthiness & flight-test Engineer by profession, I survey, test and approve / disapprove new and modified aircraft designs from drawing board to C of A. In between I do about 70 hrs pa of either private flying or low grade airworthiness test flying as either pilot or observer.
Critical AoA doesn't change by and large (actually it does at very low or very high airspeeds, but most aircraft never reach either end of the scale) with either loading or airspeed unless you have a particularly flexible wing. However, by deploying flaps or slats you change the aerofoil section, and almost inevitably the critical AoA with it.
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