The AP2112 is CMOS process low dropout linear regulator with
enable function, the regulator delivers a guaranteed 600mA (min.)
continuous load current.
I looked into many Arduino boards and mostly the documentation says 50mA for the 3.3V output pin. That is just a number that is on the safe side.
I think that your guess is just as good as my guess. There is no definitive answer, and there are no guarantees. If you need 500mA and it does not get hot, then it is okay.