Even outside of flushdraws he has JQ, KJ, KQ a decent amount, maybe even 87. Sucks to hold the Ad but I would call this down.

I agree it sucks having Ad but personally I still ch/c if I get here. We have lots of worse overpairs to fold, such as JJ and QQ with diamond which also heavily block his bluffing with QJ. We have plenty of missed draws ourself that will ch/f river, depending on how many of them we raise with earlier. It's also not impossible for him to be aggressive on the turn with KQ or KJ as these hands look like they have 10 good rivers. If he calls low SCs preflop then he can possibly have more missed draws with no showdown value, 87 for example. I am not saying his PSB is weak but he can potentially turn up with lots of bluffs despite us having Ad, so we want to be correctly balanced between call and fold and not overfold.

If I am in his shoes with AXdd on the river I check back because of showdown value against your missed draws, so I don't think having Ad is as bad as some other diamonds.

What are we calling with in this spot? AA/KK with no diamond would (but you don't have these as you said you ch/r flop), what else are we calling down with aside from TX? If you are always going ch/c ch/c with your TX on this board it makes folding AAd more ok. It's unlikely but not impossible for them to valuebet a worse hand, although the sizing puts me off that idea.

Overall I think this decision is close and it's not a massive mistake either way vs unknown. I think blocking AT is small but nice, weaker tens may go smaller sizing.

I doubt regs will have many Tx here, ATs-JTs,T9s. ATo can be close but vs 3x and non spazzo recs from the blinds it is a fold.
And Ace of diamond quite nice fine blocker because

some

people not bluffing it.

Vs rec it is ugly still can bluffcatch. Not exciting tho