Here's a bit of a hand that leaves a bad taste in your mouth. I'd like to know if I made a generally good decision, and if my analysis was okay. The hand is 9max, but I've only included the relevant stacks.

UTG $120
MP1 $170
MP2 $110
CO $50
BTN (Hero, AA) $220
SB $80
BB $100

Preflop ($1.5)
UTG (a nitty reg that I've played around 2K hands with) raises to $3
MP1 calls, MP2 calls, CO calls
Hero 3bets to $14
SB folds, BB folds, UTG calls, MP1 calls, MP2 calls, CO folds

Flop ($57.5) 332
UTG checks, MP1 checks, MP2 checks, CO checks
Hero bets $20
UTG folds
MP1 raises to $40
MP2 folds, CO folds
Hero calls $40

Turn ($137.5) 6
MP1 instantly jams $116
Hero?

Obviously, preflop action and the super dry flop makes us super happy with aces on the button. I decided to bet 1/3 pot (1/4 or checking may have even been better and gives a better price for bluffs with 54s etc.) because the SPR is so low and because I think the bet will extract value from a lot of the lower pocket pairs in my opponents' ranges.

MP1's min raise is extremely suspicious, as there are only a handful of combos of semi-reasonable hands that are ahead (that both flat vs an UTG open and flat a 3bet OOP multiway):
33 (1x), 22 (3x).

I can see how possibly villain would hold 54s 43s, or even A3s, but mostly I think that villain's range consists of 10s+

When villain instant jams on the turn for roughly pot, it's virtually never a bluff given the action. In this situation, my analysis was the following:

I don't think it's very likely villain would check min-raise the flop with 6s. I think villain would likely play 2s and possibly 3s and 54s this way. I think that villain would also play this way with any 3. However, I think it's also possible that villain would play this way with Js+, but is slightly less likely.

Again, I'm curious if anyone else has any thoughts. I'll say what my decision was after

I think you need to go back to the start of the hand to realise how you ended up in this spot. You had an opener and three callers and you 3bet to only $14. That's way too small. Ideally you want to be playing this post-flop versus one opponent but with this sizing you end up playing with three. I think nearer to $25 would be a better sizing here. If you do get one caller the pot size will actually be slightly smaller on the flop but I'm way way happier stacking off with my overpair versus one person then I am versus three of them.

As played the flop bet is again too small. I have to disagree with your assessment that the flop is super dry. It would have been dry if it was just you and the UTG opener but now you've got two other callers in the hand. They absolutely could have things like 45 or two clubs in their range. For that reason I'd be betting larger for value against drawing hands and lower overpairs).

Sometimes in these hands we can focus too much on our final decision without thinking about all of the sub-optimal decisions that were the foundation of the history of the hand up until that point.

River is a call I think. If utg is nitty there shouldn't be much in mp1 initial calling range that hits this flop. You really need good reads on mp1 to ever fold this which I don't see in your op. Without more info I couldn't give mp1 credit for having low suited connectors or even 22/33/45s.

Shoot I just realized that the board was supposed 332 rainbow. Turn may have been off suit as well. It was late and picked random suits because I couldn't remember the suits exactly.. I guess I accidentally picked 2 clubs. Does this make more sense about my opinion of the flop texture?

As for the 3bet, I can see now that this was a mistake. I'd never been in this spot before really with As on the button versus 3 cold callers, and $14 seemed like a pretty large 3bet at the time, since my sizing versus one opponent would've been $11, or little over a pot sized raise. Are you basing the $25 from intuition, or the size of the pot? As for the cold callers, my read on them after about 150 hands is that they were mostly loose/fishy/spewy--so the flop line villain took wasn't exactly an uncommon line in this game, it was clearly a top value line. Thus, I expected mostly folds with garbage (CO) or a couple flats versus set miners (MP2).

Sqzing to $25 seems terrible IMO and in fact I've never seen that kind of sizing used in game by anyone but fish. $14 is totally standard. Of course he can have sets but with SPR < 1 I'm never folding aces here in a million years. Usually I probably just jam the flop. I can see the value in calling the raise but it's always to induce V into betting the turn. It's never to fold.

I have a kind of rule of thumb for squeezing where it's 3 times the opener plus an additional bet size for each flat caller. So in this case it'd be 6x or $18. I bumped it up then because I thought it was a hand from a live session and in that setting villains are more inclined to call 3bets.

Sorry, yes it was an online game. I decided to flat the flop because villain's line is almost always super value or complete air (sometimes spewy players will do this versus small bet sizing since they think you are "buying the pot"). I figured that seeing any turn card would give me a tad bit more information. For example it's pretty clear from the instant jam on the turn that villain doesn't really care what we have. I also think 3bet shoving may turn our hand face up when the board is so dry--villain may be excited to get it in with Ks here, if he was attempting to slow play, but he could also get scared off.

I do think though, that slightly larger may have been better still, since after UTG flats (10s+ AQs+), the other flatters are getting a sick price.

Also, as far as the difference between online/live.. as long as we're taking down this pot on the flop 3/4 times (assuming we get stacked the other time), we're still making profit--so raising larger (in a live game) and most likely winning a smaller pot is just the less variance route, yes?

I originally thought fold, but the fact you didn't 3bet on the flop might indicate to the villain your not that strong. He may then feel confident to shove his over pair on the turn (you said they were loose/spewy/fishy).

Equilab puts you around 41% vs KK+,33-22,A3s,54s,43s so I'd call if I thought villain can do this with an over pair, which given you didn't 3bet otf, is a definite possiblility.

Go bigger pre, like 17, pot is 13.5 so if you make it 14 utg gets almost 3:1 and everyone behind will get an even better price. You lose to basically 8 combos, 45s is unlikely since neither reg nor fish will often raise here with a draw. Rough guess is you are flipping on whether its a fish or a reg, I'm leaning more towards fold though.

Is that the equity on the turn? I don't see how it can be 41% if we're crushed by everything except Ks, and only drawing to 3 outs max vs 54. Otherwise, seems like a pretty obvious call.

Anyway, as played, I did call and lost a pretty huge pot. Pretty sucky but what are you gonna do. It was pretty hard for me to believe that villain could show up with the hand he did. Saw the same guy lose a $200 pot a few hands later with 107o or something.

From Equilab:

Board: 3c3s2h 6s (I changed the 2 to a heart as you said it was a rainbow flop)

Equity Win Tie
UTG 40.93% 37.98% 2.95% AdAh
UTG+1 59.07% 56.12% 2.95% KK+, 33-22, A3s, 54s, 43s

BTW Equilab is a free download.