Just a couple comments for you. I agree to not 3B with your hand, but not for the reason you offered. If you had suited/doublesuited/or a better connected starting hand, I think then 3B with AAxx is standard. Also, if you are deeper, you should be 3B a wider range of hands, so I think its incorrect to say that you did not 3B because you were deep.

Flop should have been XR pot. You can probably lead turn 2/3 and feel comfortable if he doesn't raise you. Also check calling turn is ok but not as strong. Check call / check fold river.

Although we hit the flop very hard, is it ever a spot to slowplay here?

For slowplaying to be good, you need to have a decent chance of winning a bigger pot than you would otherwise do by playing aggressively. HU and OOP, this is unlikely. You will tend to win small pots because Villain is likely checking back turns and drawing for free when you call flop. And occasionally he will spike that draw and you will pay off often.

So just go out aggressively with your monsters on the flop, and do the same with some semibluffs, of course. The spot to slowplay such a hand would be against a Villain who likes to bluff, and you have reason to believe he will keep firing. Here you don't know that. He is just making an automatic c-bet in a HU pot, and will usually shut down with his bluffs when you call.

And keep in mind, free cards are death in PLO. So in general you should not choose a flop line that "forces" you to check twice to him. Because the player in position will often utilize those free cards and gain a lot from them.

An exception would be when you check-call flop to dodge some bad turn cards before you get a c/r in. Say, if you have a naked nut straight on a very coordinated board, and you don't want to c/r flop and feel lost OOP with initiative on all those nasty turns. In that case, you might want to check twice if Villain is likely to attack your check-calls liberally with blockers and semibluffs.

Thank you guys for the comments :)