A2s is a good candidate to 3bet pre-flop. I´d say it´s definitely more "standard" than flatting it. I would also consider raising the flop. Turn stab is ok and so is the river give up on a jack.

Calling flop is fine with SB and BB still to act. We wanna keep worse draws in. I'd have thought a hand as strong as a set on the flop would have bet turn as well as hero will have flush draws in his range and to get value from Jx and Qx. Not sure on river as I think hero would check back all his Jx on turn apart from QJ so not sure hero can rep a lot with a river bet

U can 3b pre as a bluff especially if the blinds are 3b, Sqz happy. If there any weaker player in the blinds call better, but anyway it's a fine call, and played it well post also i think. The river card is somewhat good for your range U had maybe AJ, KJs, some QJs, JTs maybe 13 combo for value bets, and mybe he had some AA, KQ, QT, and some kind of stuff what he can call with. He has deffinitelly a stronger range when he start cbeting 4way these kind of boards, and most of the combos he can fold on the river is FD-s. There are some better candidate to bluff with like T9s 4combo, or KTcc maybe, definitely not that much. I think not a problem to underbluff that spot because his strong range. Very rarely U can win at SD vs T9, KT or smaller fd-s too.

wp

Did villain have kqhh or aj or something else?

Well played!