Villain: 48/21, 3bet: 18%, hands: 171, Villain was potting most of the hands every street because at one point he was 400bb deep. He had had some good hands but was also caught from bluffing couple of times when I called his pot sized bombardment on the river with my second pair. Was my river reraise ok? And would you call a shove or is this always a fullhouse or bigger flush when this happens? I should have probably raised the turn but I felt that if he senses weakness he will start to bombard like he did.

SB: $10 (100 bb)
BB: $21.49 (214.9 bb)
MP1: $2.70 (27 bb)
MP2: $5.49 (54.9 bb)
MP3: $20.08 (200.8 bb)
CO: $19.72 (197.2 bb)
Hero (BTN): $21.30 (213 bb)

Preflop: Hero is BTN with 7 6
2 folds, MP3 raises to $0.35, CO folds, Hero calls $0.35, 2 folds

Flop: ($0.85) A 4 A (2 players)
MP3 checks, Hero checks

Turn: ($0.85) K (2 players)
MP3 bets $0.41, Hero calls $0.41

River: ($1.67) 3 (2 players)
MP3 bets $1.59, Hero raises to $4.08, MP3 raises to $19.32, Hero calls?

He seems to be raising a normal amount of hands pre. He has all the houses. There are likely no worse flushes.

You say he likes to pot postflop, but he checks this flop and only half pots turn. Looks very nutted to me.

Fold pre
Bet flop or riase turn

I did call in the end although I still think it might be "wrong". Villain had A7o

Not sure about calling AP. However I’m not sure why you were raising otr. It seems like a better hands call or shove, worse hands fold kind of spot. Just call villain otr; you only have to win about 1/3 of the time to break even when you flat villain’s river bet. AP you put yourself in a spot where you have to win almost half the time.