Think you play this fine, I quite like the river bet and I think it exploits his weak Ax and counterfeit A3/4... but fold 100% to the raise, like he has you bet 1000000000000% of the time here so you have to be disciplined and fold.

Played the hand perfect, I'd be b/f the river too, can't see us ever being ahead when raised. A check-call is not bad either to catch their bluffs but overall I like betting as they are calling with most Ax hand pre flop.

Pre: Standard.

Flop: Standard enough, I like you're sizing here.

Turn: Betting again for value seems correct, again I quite like your sizing here. When we get raised I would be slightly concerned but not concerned enough to consider folding ever so I call here.

River: This is a pretty interesting spot, I would expect villain to show up with a reasonable number of missed flush draws, I would not expect villain to have a ton of worse Ax after the turn raise with the exception of exactly A3/A4, we are also going to run into sets etc obviously as well. I think my preference would be to go for a check call to maximise value vs his missed flush draws but betting with the intention of folding seems reasonable. It sucks that he has raised so small here but I still think it is a fold, despite the excellent price being offered. Check calling avoids this scenario though which is a big benefit of that line, despite occasionally missing value from some parts of villains range.

Looks standard up to the river.

I think the river donk is great and not something I would have probably done myself. Once he raises though it's a clear fold. If he does have a weak Ax he's going to look to bluff catch rather than bluff himself.