Electronic – I cant find IC from code printed in ic

If you can't find a better match I would suggest giving it a try with an AO3401A 3A 30V p-channel MOSFET. That matches the voltage rating of the APM9435 MOSFET used in the other SMPS channel (sources are tied together according to the PCB layout), at lower current (~3-4A) and is also logic-level gate.

Of course it could make things worse than they are now, but I doubt it.

cannot name the manufacturer, however on my Pro Micros and Minis (all "counterfeit Chinese knockoffs" which I would rephrase as "inexpensive and reliable open source providers from China) the regulators are labeled S2PC, S80C, S80D (micros) and S8PL (mini), all with the same manufacturer symbol. I have tested the dropout voltage and measured 240 mV at 65 mA load.