A6s HU

I don't think so. And I am also folding the river as played - it might seem nitier but I cannot see what do you beat except 56..

I would cbet flop 300-400, check turn and evaluate river. We have showdown value with our hand, but tough to get value from worse especially in double paired board. Now that we have bet twice and villain donks river we are very often beat, but if we had checked turn then I would prefer to call river. Villain can easily call flop with many overcards and then try to get pot when we show weakness with turn check.

you should check the turn with your SD value.

as played, im definitely calling river for 1/3 pot. the odds are good and fish can bluff with this line HU with random airballs, also its hard to hit a FH.