Cú Chulainn

We have 48.9% equity against villain's range. We only need 41.7% to make a breakeven call. If we are competent post-flop, folding is just . . .wrong. Villain has all KJs, KJo, QJs, JTs, ATs, ATo and 77-TT in their range.

Folding < calling IMO. I'd prefer 3-betting if it was AJs and we were deep. AJo is still doing fine vs an MP 6 max opening range, so folding is way too nitty.

River is a fold vs a 5NL villain with the stats you provided. Hearts got there and he shouldn't be value betting worse than TPTK, here. Your fold is the correct play.

Resolve: I find SB ranges are more pocket-pair heavy. The Broadways that you talk about are typically 3-bet, from my experience, rather than calling OOP.

GameTheory: As this is 5NL, we shouldn't be too concerned about opponents picking up on this and floating with a wide range.

I'm folding the river. After 3-betting pre-flop and betting the flop and turn and given the board run-out, I can't see us being good on the river, if they shove. Any Jack and any 8 beat us and they shouldn't be value-betting worse. Admittedly, I'm a bit of a hero and I can't find a call here.

There are a few combinations that they can credibly have on the turn:
88, As8s, 7s8s, 8s6s, Ks8s, 7c8c, Ac8c and so on

If they shove the turn? I'm happily folding my Queens. Remember: you've shown a lot of strength by 3-betting pre-flop and betting the flop and turn.

The flop bet is fine. Personally, I'd go a little bigger (0.60-0.65). You have an over-pair and an open-ender and blockers.

I think we should be checking the turn, but a bet isn't awful. They can still have a lot of draws in their range. I would expect to get played back at a lot with a turn bet, though.

We should definitely be checking the river. There are a ton of Jacks in their range and any 8 makes a straight.

I don't really expect an unknown at 5NL to be bluffing with a busted FD, especially for this size.

In this spot, 99 is essentially a bluff-catcher.

I think that you played hand well.

C-betting the flop is fine. There is a lot of value to be had. There are a lot FD combinations and lower pairs and even the occasional gutters that may opt to float. As well as this, it also disguises your hand. Checking (presumably check/calling) here gives a lot of information about your hand away.

You could definitely consider a thin value bet on the turn. If the button had called, I'd check, as in that case the button should have a stronger range. However, the SB has a wider range here than you might think (they are closing the action on the flop). Also, SB calling ranges have a lot of pocket pairs, which he can definitely still have on the turn. A thin value bet on the turn would get value from these should they call and would pretty much guarantee that you get to showdown.

The river fold is completely fine. All of their value hands beat you (they are not betting worse than a Jack, maybe even a Queen, here) and players at 5NL don't tend to bluff rivers with bet-sizing like this.

Definitely have to C-Bet the flop. Against this player type (67/29) there really isn't any other play but to value bet.

Standard fold on the river. There are far too many hands that they would take this line for value with and players of this type very rarely bluff rivers.

Yeah, there is a lot more play in 6-max vs FR. 6-max is a lot more fun.

You could consider FR and play more tables, maybe? Just play very tight from EP and pretty loose from the button and the CO (depending on the type of player on the button, of course).