Hero (SB): $251.73 (125.9 bb)
BB: $428.01 (214 bb)
CO: $320.03 (160 bb) 27/20, very low River Aggression frequency, 1k hands so far.
He did 4b me one time with 66 in the same spot with a short fish behind.
Also tripple barreled me blind vs blind in a good spot for him and he showed pure air.
BTN: $72.55 (36.3 bb) loose passive fish

Preflop: Hero is SB with Q A
CO raises to $6, BTN calls $6, Hero raises to $26, BB folds, CO raises to $66, BTN folds, Hero calls $40

Flop: ($140) Q 5 6 (2 players)
Hero checks, CO checks

Turn: ($140) 9 (2 players)
Hero checks, CO bets $52, Hero calls $52

River: ($244) K (2 players)
Hero checks, CO bets $183, Hero folds

So with my read I decided to flat pre. Pretty happy about the flop and didnt plan on folding unless a heart hits. However he checked behind and I guess I should have bet against random pp's and KQ.
As played I figured the K hits his delayed cbetting range kinda good as some combos AK hit and KQ improves as well. Im having a very hard time to give him any bluffs but if I would add a random pp like 77 to this range:

QQ,99,AdAh,AhAs,AhAc,KdKh,KhKs,KhKc,AhKh,AhJh,AsKd ,KdQh,KhQd,KhQs,KhQc,KsQh,KcQh

then the call would probably close to breakeven including rake.
I ended up folding because his low AFq also and I didnt had enough timebank as well as other tables running.

Thoughts guys ?

exploitively at 200nl i think betting turn yourself is prohibitively better.

very confused about his line postflop... his river sizing seems so bluffy to me. people in your shoes have TT-JJ an enormous % of the time after turn action so i would expect most people think you'd be doing a ton of folding on the river against this betsize... like it's just so hard for me to see anyone betting AK/AA like this, so i think if you're beat it's very likely to be a flop slowplayed flush - BUT EVEN THEN those hands will frequently not checkback flop when you have a lot of Qx in your range that might end up getting away from their hand on a heart turn. of course, a strong player should certainly have a balanced checkback range, but i expect that much less at 200nl. i think i might go out on a limb here and call everything for that reason. it's just so hard for me to see anyone betting AK like this and AJ w/ a heart, A7, A8, A5, T8s, or potentially even just some totally random hand like 33/A3s could all conceivably take this line.

by the way, i would expect that 1k hands isn't enough to have an even remotely accurate sense of river aggression frequency. for example, i just pulled up the stats on a semilaggy fish on whom i have 984 hands, and he has been able to bxb only 14 times, and river cbet only 6 times! i feel seeing the 66 hand and a pure air triple are much more instructive. in my experience a player who shows down those hands is gonna end up overclowning around a very high % of the time.

Bet / fold turn - as played it's a coin flip between folding and calling.

I think the river is a very easy call for me.

The problem of folding on the river is that villain can make the turn bet with any two and decide to continue to bet a scare card on the river.

So what mythrilfox said.

Depending on how your turn checking range is constructed, i'm not sure we need to call this combo to this sizing.