I think the LAG player type to go either way on river to be honest. I have seen stranger things in these type of games.

If he puts our hero on a hand like AdQs (Non-spade ace/high-spade kicker) after calling his huge turn bet he could take the As/weak kicker line as a bluff. He bet less than half pot on flop and over pot on turn. A high ace in our range could make sense to this player type.

But either way, we can eliminate the As from his range because we hold it and enable us to make this fold.

Against a LAG you have to 3bet AQ for value preflop, especially with the dead money of the caller.

Turn call is good

River feels like a fold. I can't see him value betting worse and your range has a lot of stubborn aces that he knows will call a lot.

Shoving the river is interesting in my opinion.

Mix in some 3b pre. AP we are set up for a great river shove as this is our worst AsXx we show up with here.

Shove > Fold > Call

If villain is a capable and thinking one, I will shove. This is at worst a 0EV play if we got our ranges right. We don’t have to even consider if he can fold flushes since our play will be unexploitable.

If villain is someone who only bet/bet/bet with hands, then I will exploitatively fold. Reads will be important here. This could be a play that maximise our EV

The worst will be to call, especially with the near PSB. AhQs might be even a better hand to call than AsQh due to card removal effect.

Joke or serious?

I think 3-betting someone under the gun with AQ off is is risky because you're going to get 4-bet a lot with premium hands. Exception would be if you've seen this guy open from early position a lot but just being LAG to me doesn't say that much about his UTG opening range. I'd be more inclined to raise the flop because I think this is a good semi-bluff to work in a raise as a set or small flush would raise as well. I think he's almost never got a flush on the flop with the A blocker and very rarely a set so I think if he calls we're probably doing okay against anything but AA, maybe he calls AK with king of spades. On the river it's a tough spot but we're getting better than 3-1 to call and if we've never seen this guy before and he just seems decent from what we've seen I'm inclined to think that there's probably some leaks in his game or he's still learning so I'd lean towards calling even though blocking a lot of the missed flush draws is a very valid point. I think he might just have a gorgeous big pair and can't let it go on the ace and he did bet kind of small on the river which is usually a sign of weakness against amateurs. LAG's I think have a default to go for it with big hands and if he's not great he probably didn't think through that it might be best to bet smaller on the river.