AQo

With out reads I think you played it fine. It's unlikely you're gonna get called by worse hands, therefore only a better hand is going to call ( small pairs etc.). Betting would be purely trying to get these better hands to fold, which I don't think you need to do seeing as you have SD value

I'm checking back as well... against a good SDbound TAG I might valuebet this as my 3betting range doesn't hit this board and he's gonna call with any weaker Ax and stronger Kx. Any reads on this guy? Against a passive fish I'm definitely checking as he still has every pair in his range on the river, against aggro fish I'm also checking as I hate to get checkraised from him.

With no reads check back but against a solid tag who had raised a pair somewhere i valuebet against lower Ax. Just K5 or A5 has hit on the River and sometimes he donks out with that hand, avoiding a checkback from a pair or attempting to get herocalled by Ax type of hand etc. But with no read and the higher chance that he may have check/called a pair and he does have more combinations of x5 he peeled again with on the turn i like checkbehind!