TJ straight river decision

Some kind of read would help us a lot. I think we have to fold OTR. Except that I think it´s well played. Maybe the turn raise can be bigger.

I would fold JTo already preflop. But as played your flop bet is ok. So is raising turn.
OTR you have to win almost 40% of the times to call profitably so now you just have to put villain on a range and check your equity with Equilab

It is true that he doesn't rep flushes when he donks turn. But he really doesn't rep sets either because I believe he would most of the time raise those on the flop. Also I don't think sets will shove river when flush completes. You might be splitting vs another JT, that would make sense, but villain has JcTc with a flush in his range too.

MP2 53.13% 50.00% 3.13% JhTd
MP3 46.88% 43.75% 3.13% AA, KdKh, KdKs, KdKc, QdQh, QdQs, QdQc, 8d8h, 8d8s, 8d8c, AQs, JTs, Ac7c, Ac6c, Ac5c, Ac4c, Ac3c, Ac2c

If we give him all AA, 9 combos of badly played sets, AQs,JTs and some amount of flushes it looks like you can call. But I'm not sure how accurate this range is. As I said he might not go crazy and shove river with anything else then flush.
So folding is usually a good option here but I don't completely hate your call since we have a great bluff catcher.

I would give him either AcQc only or all AQ. Why would you only give him AQs? I think the riverplay does not really make sense with any AQ except AcQc though.

As for JT, it is not clear if he wil have it UTG+1, so let´s just give him just the suited versions. Both AcQc and JcTc could cbet or check-raise on the flop, check-call looks less likely to me.

I would also expect all sets to bet the flop, but sometimes weak players kind of freeze with a set and autocheck regardless of board texture. As his whole line seems strange, he might well be one of those players. So let´s just give him 3 set combos, for the sake of simplicity all QQ.

AK makes a little sense in my opinion, he could check the flop because he does not want to bet 3 streets. Then he leads turn and shoves river hoping hero has more worse 2pair combos than flush combos (obviously hero has almost no set combos given the board and the preflop action)!? But as AK will also bet out on the flop quite frequently, I would reduce AK combose by half. So 6 combos.

A weaker player might also overplay A8 that way (if they play it from utg+1) But as there is no read, I would just leave those out.

Actually, I would not give him all AA combos. I am sure AA would bet this flop the vast majority of the time in a single-raised pot. So I would maybe give him 1 AA combo.

Now the question is what other flush combos does he have? Let´s just give him AcQc,AcJc,QcJc,JcTc,Tc9c,7c6c and 6c5c and Ac5c,Ac3c,Ac2c. That is 9 combos. As we expect him to c-bet the flop a good measure, I would reduce it to 5 combos and just pick the ones he could conceivably check-call the flop with, which are in my opinion the stronger ones so let´s give him AcQc,AcJc,QcJc,JcTc,Tc9c. With these one could arguably also justify a turn raise because some of them make a straight, some of them make a straight draw in addition to the flush draw and AcQc also makes 2pair.

So my range would look like this:

QQ,AhAc,AKs,AcQc,AcJc,QcJc,JcTc,Tc9c,AdKh,AdKs,AdKc,AhKd,AsKd,AcKd

As you can see here, against this range, you have a comfortable call:

Board: Q♦K♣8♣ A♠ 4♣
       Equity     Win     Tie
MP3    33.33%  33.33%   0.00% { QQ, AhAc, AKs, AcQc, AcJc, QcJc, JcTc, Tc9c, AdKh, AdKs, AdKc, AhKd, AsKd, AcKd }
BU     66.67%  66.67%   0.00% { JdTh }

What happens if we give him all 9 flush combos?

Board: Q♦K♣8♣ A♠ 4♣
       Equity     Win     Tie
MP3    47.37%  47.37%   0.00% { QQ, AhAc, AKs, AcQc, AcJc, QcJc, JcTc, Tc9c, 7c6c, Ac5c, Ac3c, Ac2c, AdKh, AdKs, AdKc, AhKd, AsKd, AcKd }
BU     52.63%  52.63%   0.00% { JdTh }

We still have an easy call.

Finally, I left him at 5 flush combos, and removed all AK combos:

Board: Q♦K♣8♣ A♠ 4♣
       Equity     Win     Tie
MP3    55.56%  55.56%   0.00% { QQ, AhAc, AcQc, AcJc, QcJc, JcTc, Tc9c }
BU     44.44%  44.44%   0.00% { JdTh }

Still a call.

You would only have to fold if he had no AK, but all the flush combos (and no bluffs, of course, which we haven´t accounted for at all).

Maybe the fact it is a big overbet polarizes his range, so he actually never plays sets (maybe except 1 combo AA) and 2pair that way, only flushes and AcX blocker bluffs. If that were the case, it depends on how often he has blocker bluffs. I checked: if he has 6 combos of AcX,you have 50%, if he has only 3, you have only 37%, i.e. with 5 flush combos and 1 AA in his range). In this spot, it is not easy for him to have blocker bluffs, since if he has AcKx, he would not need to turn it into a bluff, same for AcQx, so it could only be AcJx if he has a half decent utg+1 open range.

If you play against this villain regularly, it could pay in this spot to just call and make a note.

Calling an UTG open with JTo is awful. No offense.