I notice that you are always spazz bluffing. You need to cut down on your paranoia and suspicion IMO - I have been spazzing out a lot on Ipoker and lost a great deal of money recently.
His 3bet of 6.7 is a bit on the high side for 8max games but you are UTG, his range here should be narrower than you think. Just fold preflop. Your donk on the flop also doesn't serve any purpose and your check/shove doesn't accomplish much on the turn cause he is snap calling any overpair which is half of his range. You can't rep that much, maybe 99-JJ
As a general rule, when you're OOP, you either 4bet or fold. flatting a 3bet OOP is as good as burning money without a proper postflop plan (is your plan to check/raise or donk any rag board?).
In your case with AQ, I think I'm definitely 4bet/getting it in if his 3bet% is above 15. We might not be in great shape when we shove but the dead money that we are taking down will compensate the times.
3% range = JJ+/AK
3% range is 1/5 of 15%
80% of the time, you are taking down 10BB preflop
20% of the time, its a preflop shove
AQ has 29% equity vs JJ+/AK (let's round it up to 30% for simplicity's sake)
(0.80*10BB)+(0.20*-40BB)=0 (breakeven EV)
Anything less than 15% 3bet% is a fold for me OOP. Bluffing is just so difficult OOP.