Whenever I river bet I ask myself "Well, what do I beat?"
If this guy is as tight as a tick, he can have AK or AJ which we do beat, but he can also have two diamonds or a set and will check/call unless its the nut (maybe second nut) diamonds, since you have to have at least an A given his play and you just calling.
To be honest, I probably raise the turn with AQ. If your opponent has AK most of the time he will flat your raise because it looks like two pair or a maybe a set, in which he still has implied odd outs to win a massive pot, plus on a raise/call and the flush completes on the river and he checks, its a lot clearly what he has without risking more BB to find out information. If he raises to 40 BB on the river, you almost have to call, and you're almost always beat all the time. Very few times are tight players raising the river with air or any AX two pairs since the strength you resembled on the river.
But given you check called the turn, lets dig into your river bet. 1/2 pot isnt a bad bet, but I do think there is merit to a bigger bet or even smaller bet. If you bet 14 BBs, he may call with AK. His hand isnt the best but the pot odds
are there. If you bet more, like 24-25BB, it can perceive as if you're trying to blow AK off its hand. Or you're bluffing
some missed backdoor heart flush draw that didnt get there. You havent played many hands with him, but balancing your bluffs and strong hands here are important for later hands.
There was nothing wrong with how you played it, just stating my opinion as to how I may have played it. Good Luck!