IMO you played the hand perfectly fine (and gave solid reasons for doing so). He needs to be turning 78 into a bluff here. And even if he does, he still has a way more valueheavy range!good fold

If preflop we are playing 3-bet or fold then we have a decent amount of hands that want to get to showdown. This means we would create a checking range. AThh with a backdoor can go both ways. I feel as if this hand is too strong to turn into a bluff. Are we getting better hands to fold?

When we bet on the flop and get this turn it actually reduces our AK, AA hands. We're not betting all Ax on flop. And KJ, KT etc now doesn't want to bet. So having AX in our check/call range makes sense. Seems fine.

River you have to call. Sometimes you just have to man up and call. What are we calling if we fold this? Are we slowplaying so often on the turn that we can fold AT and not be exploited? Doubtfull. We also block Ax and JT.

Line seems ok, I would definitely use bigger 3b pre OOP and possibly smaller cbet sizing. I am only calling with specific info about villain, I don't think population can bluff enough on this river.

He has loads of possible valuebets and I can't see obvious bluffs. This is also a scary board to bluff into against a 3bettor. Maybe his TT/JJ is supposed to bluff.
Maybe he gets here with weaker AXs bdfd and doesn't realise he is bluffing.

His possible value range: AQ, JTs, 88, KQ, some weighting of AK and QQ. He would need a fair amount of bluffs to make river call profitable.

I suspect you have given yourself a very narrow range when you x/call the turn, possibly you only have AJs and ATs. Can you have KQ or AQ with that line? Maybe you have KJs? If you can have lots of weaker suited aces then in theory you will have to call ATs (better bluffcatcher with the straight blocker), whereas if you have lots of stronger hands you can fold ATs. It would be interesting to see how a solver plays their range here.