I would bet much bigger on the turn! By going half pot you are making his life easy with 2 pairs, sets and worse flushes! You need to extract max value from these and charge them to improve! His hands he is going to fold to 80% pot he is probably going to fold to 50% pot anyway!

I'd have 3bet this hand pre flop as I don't think it's strong enough to call.

Post flop your line is fine, turn bet needs to be bigger and for me the river is an easy bet fold.

Pre: I would be opting to use this hand as a squeeze preflop rather than flat calling it, KJo will not play too well OOP vs multiple opponents without the betting initiative.

Flop: I like calling the SB donk here, folding seems out of the question with the 2nd nut flush draw plus two overcards to the board.

Turn: When checked to I don't actually hate checking back here for deception. Normally I'm a huge advocate of bet bet betting relentlessly for value but this seems like a board where getting two streets of value is going to be difficult, by betting we will fold out almost all 1 pair/worse flushes and probably a decent chunk of 2 pair hands as well. Sets will likely call to try to fill up and obv the A high flush is not going anywhere and maybe some of his stronger flushes such as Q/Jc. By checking we allow our villain to try to hero call us with more* worse flushes and some other worse hands on the river.

River: When villain check calls our flop bet and checks to us again I expect to be ahead here often now so I do like going for value again on the river. When we get raised then it is a trivial fold, opponent will not be bluffing here enough to make calling even close to profitable.

I would fold pre. Overcalling this type of offsuit hand is going to lead to too much trouble. I'm also not a fan of squeezing OOP with this hand type, especially versus an UTG open.

Post flop looks ok. I agree with Fergs that checking the turn has merit but I think at 5NL we can still just simply bet twice and fold to a raise. At least this way we don't allow sets a free shot to outdraw us, and I would expect plenty of worse flushes to call us down.

Thanks for the insights