$10 NLHE 6-max: Too nitty fold?

Villain from MP opens 3bb, Hero from BB calls with 5d5c.

FLOP: Ks9c5s, Hero checks, Villain bets 6bb and Hero raises to 19bb, MP calls.
TURN: 6s, flush completes, Hero checks and Villain bets 22bb, Hero calls.
RIVER: Ad, Hero checks and Villain Shoves 56bb. Is it Call or Fold?

Played on unibet, no hud, no info.

Fold looks fine.
Villain represents with his line only a flush, and he has all the flushes in his range.
Villain bets on turn only flushes and sometimes slowplayed sets KK, 99.
AK, QJ, J10 ect. should check back the turn.

I probably just bet call here with a set as villain can gii in plenty of pair plus draw hands.If villain has the flush we still have a decent amount of redraw equity ourselves. Check folding doesn't seem like an option on the turn so it's the only line i really like is to just bet and commit to the hand.

Would just call on flop as calling allows worse hands to keep betting. You check-raise he calls would limit his range primarily to top pair good kicker and better or a flush draw.
The turn completes the flush draws and villain bets 22 BB (is about 50% pot) and puts you in a tough spot against a bigger bet you might consider folding right here as your OOP. But he gives you great odds to call on the turn and you might improve to a fullhouse or be ahead already (although not likely). On the river I would just fold you arrived here with bottom set, one of the worst hands you should have in this situation. It is not nitty to fold your worst holdings in this situation.

When you CR the flop your range is pretty capped to flush draw, two pairs, set or some A9 to your opponent.

Check call the turn is fine since he can still bluff you with a As. And you have equity to improve your hands to a full house.

I dont see there are a lot of bluffing on the river. Fold your set is the best choice. Call is fine only when your stack are short enough.