Are you bluffing on the river?

yes hoping he layed a weak flush.. bad?

I think it's pretty bad. You're giving him a pretty good price, and I don't know what weak flushes he has that don't raise the turn:

I mean, it's a 3bet pot, so he likely doesn't have that many low cards in his range to begin with. If he does play low cards, they're likely suited connectors or something, which means he would have made a flush on the turn. Given that he's OOP and there's not much behind, he'll raise almost all flushes on the turn, so I think it's very unlikely he plays any low flushes this way.

If he plays other connected cards with 1 club, they either hit a straight on the turn that's raising, or two pair, so they don't get to the river this way. All his other club are high broadway clubs that are part of a pocket pair, or stubborn broadways, and he's not folding those.

You probably move him off a weirdlly played chop (though it's hard to have AK without the Ac or Kc), a worse hand, or like a weird two pair that didn't raise. I'd say 90% of the time he folds you had the best hand. That said, I don't think he folds a flush for this price, so when he doesn't fold (I dunno, maybe a third of the time?) you lose. So when you shove the river, you win 6.7% or so of the pot that you wouldn't expect to win, and lose 33% of your bet. Just check man, you have the best hand.

BTw, I obv just made up the numbers, but he seriously rarely lays down better, and you have shitloads of showdown value.

ok that makes sense thanks for the detailed explanation

Weak flushes he has are probably stuff like a stubborn 88+ with a club, but I don't think any of them are folding. Six Macks is right, check behind and collect the pot from all his non-flush hands, because I don't think he's folding anything better or calling anything worse on the river.