AKs

Since you capped the flop, and I think this is the correct way to play the hand, I would bet the flop or your pretty much flipping your hand face up. AQ,KK,JJ,TT,99, I think you bet the flop with these hands, so checking AK and AJ the other capping candidates, are about the only hands you can check.

As played, I call flop, and I think calling the turn is correct. I don't think you can raise the turn as only Qx raises and flushes call, the rest you don't mind continuing to bluff.

I would donk the river as flush and Qx shouldn't bet, maybe a bluff will bet but a 69/4 seems too passive to bet the river; however, Qx might bet, I would guess the case here and you got the raise.

Preflop: Fine

Flop: You can't bet for value and you can't bet as a bluff. The only reason to bet is to hide your hand strength. This can be an expensive habit 4-ways. I'd check myself. Multiway pots call for more honest play.

Turn: Clear check-raise. You generally have the best hand and there are plenty of draws that should pay. Even a donk is better than a check-call. Relying on the button 3-barreling in a 4-way capped pot with weak hands/missed draws is too optimistic.

River: As played, I don't know. But check-raise flop, bet river, and you'll get on average two bets out of him. Your line got lucky this time.