EXAMPLE:
Pre Flop: ($150)
3 folds, LLinusLLove (BU) raises to $253, 1 fold, OhHeyCindy (BB) calls $153

Flop: ($556) 4 2 K (2 players)
OhHeyCindy (BB) checks, LLinusLLove (BU) bets $170.81, OhHeyCindy (BB) calls $170.81

Turn: ($897.62) Q (2 players)
OhHeyCindy (BB) checks, LLinusLLove (BU) bets $1222.89, OhHeyCindy (BB) calls $1222.89

River: ($3343.40) 3 (2 players)
OhHeyCindy (BB) checks, LLinusLLove (BU) bets $9823.93 (all-in), OhHeyCindy (BB) calls $9823.93

Total pot: $22991.26 (Rake: $5)

Showdown:
LLinusLLove (BU) shows 7 T (a flush, King high)
(Equity - pre: 50%, flop: 51%, turn: 32%, river: 100%)

OhHeyCindy (BB) shows 5 5 (a pair of Fives)
(Equity - pre: 50%, flop: 49%, turn: 68%, river: 0%)

LLinusLLove (BU) wins $22986.26

I assume that LLinus would 3x pot jam river with flushes, and bet stuff like two pairs and set with a smaller sizing like just pot size bet.
With regards to bluff, is it correct to say that we would jam with heart blcokers like AJ/ JT, and pot size with bluffs like JT?

The heart blocker bluffs can bet any size since they block calling range and x/r range. The non-heart blocker bluffs at most can bluff with nai size, since they don't block the calling range vs 3x pot ai.

It's possible that JTcc is indifferent with bluff/check on river (and can never jam), but with a heart blocker you should always bluff. Imo Jh is not the best heart blocker actually since you want to block Qxhh followed by Axhh the most, and QJhh 3b pre a lot bb vs btn and AJhh is 100% 3bet.

3x pot jam means he is giving you 4:3 odds on a call. So he must have 4:3 value:bluff ratio to make you indifferent.

At this river he can have a total of 45 flush hands total. There must be 45 * (3/4) = 33.75 bluff hands. Let's make it 33 to be conservative. But wait a second, if you hold a heart blocker then the combinations are reduced by 9 making it 36 value hands with 27 bluff combos.

Your opponent should either make you indifferent with blockers or without. I think going with, is better since you are more likely to be calling the flop and turn while holding a heart.

I probably would not be overbetting turn and river without holding the nut blocker as a bluff. I probably wouldn't take this line for value except when holding the nut flush. I wouldn't bluff J T on this river. I probably wouldn't do it with J T either.

Except if you know villain is stacking off on that board with a pair of 5s, in which case you can considerably widen your value range...

But seriously, as villain should be more inclined to call with bluffcatchers which contain (almost-)nut blockers - on that board for instance KxQh or AhQx - doesn't it kinda make sense to have non-nutted flushes in your value range as you increase the likelihood of actually getting called by those hands?

Either way, I suppose we can reasonably assume that not all 45/36 flushes would take that line, which in turn reduces the number of bluffs we need.