Played this on mobile so not got a good replay sorry.

$3 888 9 max regular sng.
UTG (HERO) 53bb Ks Ts Open to 2 bbs
HJ 15bb folds
CO 30 bb folds
BTN 40 bb folds
SB (Viillian) 58bbs flats,
BB 22bbs folds.

5.5bb in pot
Flop As Kh Th
Villian checks
Hero bets 3.8bbs
Sb calls

POT: 13.1

Turn Qs

Sb bets 6.5bbs
Hero Calls

Pot is roughly 26.2

River 7h

Sb bets 13.1bbs
Hero Shoves for roughly 43 bbs

Not super sure about the turn call, might be a shove there but i think Jx calls far too often and i have a good amount of equity to realise and pretty nice implied odds if i boat up/ flush up/ Royal up.

River I think calling is by far the worst option, his range is so Jx heavy that calling is losing farrr too often. Not sure whether having the Ah is better for me cos I obvs block the nuts, but as i said i don't see him donking a heart flush draw very often. On top of that I block KJ and JT so its a decent card to turn it into a bluff in case he does somehow do this with a better 2 pair than me. Also I realise that I'm very rarely bluffing in that spot, so it makes a nice spot to do it, and with us being the biggest stacks by far it makes it even LESS likely.
I think folding was also a good option

Is far too often just your understatement for "always"? lol

I actually really like the thought process. It's a really creative bluff... like one you'd see on a youtube/podcast hand breakdown that a pro played vs a pro, but I don't know how well it flies in $3 games. The hands you're targeting are hands that are hard to fold for many players. I guess it depends on the villain. If he's shown to be scared of MUB and fold on every scare card, sure. The thing is, you're taking a polarized line vs (what should be) an already polarized range (again depends on villain; maybe if he value bets bigger and this is a capped/block bet sizing for him). If he is doing this with just straights and flushes, he can easily call the flushes, and decide the straights based on blockers. Makes it too easy for him to play perfectly against this move.

As to your blockers, you unblock AJhh and other AXhh like you said, but as to what you said about blocking KJ/JT... I thought that's what you think you are targeting to fold.... shouldn't you want to unblock that? I don't get the value of your hand blockerwise on this runout.

End of the day it does suck to call or fold this, which makes it great to consider the option of raising, but it's also a tournament. Your ICM bump for taking this down is like 65%, but -100% when snapped. So you need him to fold even more than such a move at a cash game. Basically you need him to have played all his jacks like this on the river AND not thrown flush draws in on the turn AND fold those jacks on the river. It is possible, but it's asking a lot. It depends a lot on how you range him I guess, which like you said, is surely Jack heavy, but the board itself blocks a lot of his two broadway jack hands. I don't know how wide he's defending from SB. Maybe it's more with a big stack, but if so, this also gives him more JXhh for his range anyway. Agree donking flush draws seems weird, but so is donking in general (at least compared to how most hands play out). He could be a fish that has nut flush draw and top pair and doesn't want to have to suddenly lead river when it comes in/wants to set the price to see the river or heck even just take it down with that top pair now because "that queen made it scary and top pair is a good hand and who wants to see an even scarier river" (again this is just what I've seen from some players at these stakes; don't know the opponent). Conversely, he could be thinking and know you don't have a ton of jacks to start with from UTG open, and that ones like KJ/JJ might make prime hands to not even cbet flop anyway, and so he leads with a ton of his jacks plus some other hands which may or may not include flush draws based on his range advantage. Anyway, I'm kinda rambling. Definitely don't think definitively bad, just very high variance and relies on assumptions I at least wouldn't be confident in. Very interesting spot, though.

hmmmm thanks for the insight, I think the most prevalent take away from this is that it would have been far much better against a better field with a more sensical donking turn strategy, cos i now kind of realise i threw the possibility of him donking the BDFD as i would seldom do that myself. Im now questioning my thought on the blockers because I think you may well be right. I think my thinking was, i did unblock AXhh but by blocking the J, its slightly more likely he has 2 pair or that hes making a bit of a donkey play with a random bluff and less likely that he has that difficult decision with the J. Maybe thats wrong though because on saying this I realise all of the 2 pairs (and i guess sets) he could likely have I block.

Also out of interest, I noticed you said it does suck to call or fold this... to me i think calling here is out of the question as I only have a bluff catcher. Is there a merit to calling I'm not seeing?
Also out of interest, is there any exact way to calculate that ICM bump?

Thankyou though i think its deffo one of the riskier bluffs ive taken in my career aha

This is large spew. Your winrate will almost always get throttled if you're attacking strength in low stakes sng's, you want to attack weakness. Jx is effectively the nuts to any fish playing a low stakes game.

Having said that I think being aggressive and creative can add a lot of fun to the game, just understand that it usually won't net the most winrate and being wrong several times in a row could create a tilt spiral. So if it brings you enjoyment and doesn't make you tilt when you get called, go nuts.

These two statements are kind of contradictory. You can't really say you block him towards bluffs and also say you can't call with a bluffcatcher. He either has enough bluffs here or he doesn't. And the thought of wanting to turn this hand into a bluff because he has bluffs is basically against core poker theory. It's like a toy game where 2 players can only have A, K, or Q and he's polarized himself to have A or Q... you'd never turn a K into a bluff. Only makes sense here if he is turning better two pair INTO bluffs himself (which he doubtfully is) OR would have an unbalanced calling range against your line. Also the fact that he is "less likely to have a difficult decision with a J" is almost precisely the issue; you make it easy for him to snap you with a flush and fold his hands worse than a straight (e.g. snap with an A and fold his Q in the toy game example).

https://www.holdemresources.net/icmcalculator is a good start. CardRunnersEV also has a free calculator.
Input should be straight forward. Let me know if you want basics in how to interpret the output (or how to let that guide decisions in tournament formats).

So good.

Additionally if we're going to bluff, would much rather use something with a relevant blocker (hearts).

Not a good spot to bluff. Villain has lead twice and is going to at least a straight a good percentage of the time.