In a sticky spot with ATo

[Eihli]

$100 buyin multi. 150 entrants 80 remain 20 pay. Blinds 75/150 I have 2k in EP2 and raise to 450 with Ah Tc. No read on BB who calls with 2.5k.
Flop Ac 3c 3h.
BB bets 500. I call.
Turn 2c
BB checks, I check.
River 7h
BB bets 350, I call.

I don't like how I played it but I can't see why any other line would be better. Folding the flop seems weak since a lot of bets come from pocket pairs and weaker aces. Betting the turn seems bad since I'll only get called by a better hand. Should I have pushed the river maybe?

Results later.