[Aceium]

I wouldn't flat call the preflop 3bet, even if I wanted to set up a big pot. I want to get more money in the pot as early as possible so I can set villan up to get all his money in with a weaker hand, even KK. I think KK could make sense for him here. He checks behind you thinking that you would have bet the flop if you hadd AQ or a set. He takes a free card on the flop and calls you on the turn because the deuce isn't likely to help anyone.

The river kills your hand by putting a 4 straight on the board and he knows this if he's putting you on AA. So his range could be anything from KK to any K, or any other PP that he would 3bet you with. I think this is a good river fold. You didn't have to get to the river this way, though.