This looks like a clear jam to me...
Keep in mind that Villain arrives with a fairly strong range OTR. So what hands exactly do you expect villain to bluff the river with?
So villain will wake up with some boats here and (just because he is loose) with some more mediocre flushes: JhJx/QhQx/KxQh/AxQ hand so on...
I also doubt that villain will turn 77-99 or random Tx into a bluff often.
As we loose our stack to boats anyways, I don't want Villain to check back any mediocre flush that might be able to call a jam

That was exactly my thinking as well. I jamed and get called by 66 making villain full house on the river.

One think I didn't like for sure in my play is the turn sizing. Should be like 24BB.

I like your turn sizing and would even consider betting less. Monoboards are usually played more passive and with smaller sizings...So I guess my choice would be 1/2 OTT

My thinking is just to have a bet size on the river that is not an overbet. And I think that for fishy players this might be more tempting to call bet that is not an over pot. But maybe this is only in my head :D
But I like my sizing flop. I think going bigger is an error.

Feels like a clear bet/bet/jam spot.

On a side note, I am noticing some sizing inconsistencies preflop. In this hand, you are 3 betting 4.5x the open (2bb open to 9bb from SB). In the QTs hand, you 3 bet to under 4x vs a CO open (3bb open to 11bb from SB). I get it, positions are different, etc. but guys paying attention are going to pick up on this. I would recommend you simplify and go 3x in position and 4x out of position.

I 3betted min raise 4x but then I thought that it is to low. Now I am thinking that I should go even larger to 10BB. And against 2,5-3BB open I play always 11 BB.
Maybe when I will move to 25NL(hopefully one day) then I will rise it to 12 BB but for now I don't feel it makes any difference.