The river bet needs to work like 38% of the time, he rarely has a 7, he rarely has trips here since I imagine they will raise the flop at a very high clip, he can show up with some slow plays like 55 88 or 99 - his 55 combinations should be a bit discounted since not every player defends that hand pre and if he does he sometimes raises otf or ott.
He will most likely show up with all combinations of 99 maybe we can slightly discounted it since it sometimes raises ott. I wont give him either 87 or 89 since its discounted from the start since not every player defends those things at these stakes even being IP, and he would raise somewhere most likely. So imo he will have around 5,5 combinations of slow played boats here.

He could still have some flush combinations, though those often raise ott or even sometimes otf. Plus we obviously block the nut flush. Lets give him like JTss and QJss for flushes.

This leaves us with 7,5 combinations that wont fold and beat us otr. I'm not sure if we should include some 77 combinations e.g. the once with a spade maybe? But even then we would need to discount them since they wont always call the turn. But yeah lets keep in mind that he might have a bit more than 7,5 combinations of stuff that wont fold the river.

Now to the part of range we are targeting here mainly: TT JJ QQ - its kinda hard to actually say how many combinations of those hands he will have since they might raise on an earlier street aswell and QQ will 4b at some freq. Lets say he will get to this river with 2 combinations of QQ 4 combinations of JJ and 4 combinations of TT (is that a realistic assumption?). So we are at 10 combinations here so assuming he pretty much always folds those otr we should have an easy bluff spot?

He might get to the river with AxKs as mentioned earlier, though obviously those combinations 4b pre at some freq at least, though if they just call pre im pretty pretty sure they will float the flop and the turn.

So with my assumptions of the tedencies/ ranges of the player pool we have a hugely profitabel third barrel here otr. Would you agree? Keep in mind the bluff needs to work 38-39% of the time. So villain can call 60% of the time and we will still be gucci. With my assumptions villain will call about ~40% of the time.