Wouldn't he check/raise his sets OTT? Why would he donk them? If he's checking and hero bets hero is pretty much commited and he can easily jam

Hero has shown nothing but strength preflop and on the turn betting into 2

and we can rule out that MP is flatting the flop to keep UTG in because UTG already folded

Wouldn't he only donk 1pair hands that he's afraid with here like TT/JJ/QQ, scared that hero will spike a K/A River and he won't get action from AK here ?

The main reason for donking is beeing scared of not getting a bet in, like hero has low Turncbet also as a semibluff

If he wants to get stacks in why doesn't he wait for hero to bet? It's super unlikely that he won't get bet into

Esp. on a board where the flop is kind of dry and the turn bricks

Yeah possibly, or the fact that he believes he has a strong hand that can withstand a raise.
I'll def donk that turn when i know i can beat QQ, KK or AA that the better is representing.

I wouldn't say he'll donk one pair hands at all.

If i'm strong - Set, top 2 pair, i'll donk into someone who has shown strength in the hope i'm getting raised. Then i'll move all-in over the top.

Personally i'm not saying i'll fold this everytime when i'm in the hand because there are plenty of fish at 4nl that will donk with K9 for example. But overall I think we're beat here in this instance

I think you're giving too much credit to this villain's intelligence. Someone playing 36/6/1.4 doesn't know how to maximise value. They just think "Wow! I made two pair, I need to bet!"
Check-raising with 2pr or a set would be standard for a thinking player. For a fish, donkbetting is the first choice.
I've called or raised way too many fishy turn or river donks this week. I think I probably won about 5% of the time.

Thanks for all the feedback guys. I hated folding on the turn but villain's low aggression level just made me feel like he had it.

As an aside, I don't think a 1.4 aggression factor is really that low when you're playing 36/6.

fold AA now