Preflop and flop seem good to me. I think you can mix 4betting and calling with a lot of your range BTN vs SB, and that includes JJ. Raising flop is probably an overplay - you'll have sets and big draws to raise. Not sure we want to expand that raising range even more.

I like a bet on the turn. I don't think the typical 50NL villain is structuring his ranges well enough to put you in a spot where you're massively value-owning yourself, or even checkraise bluff you off your equity. Instead, they're checking hands that either want to check/fold or check/call, either of which is perfectly fine with you.

As played, you have some single diamond hands to call with, and probably even have some non-nut flushes, so you're pretty far down in your range. Fold seems prudent.

Villian has a 10% 3bet range. Do we always 4 bet here? why?

Sry, I might be clueless but... do you mean 10% 3bet right? I've always see the 4bet ratio (or 4bet range) define like this
This statistic is intended to show what percentage of all hands a player is willing to 4+Bet with given that he raised. For example, a player with a PFR of 20 and a 4Bet of 5 raises 20% of hands, and 4 Bets 5% of those; 20 * 5 / 100 = 1. Thus this player has been shown to 4+Bet 1% of his hands.

Pre- I would never 4bet here I think his ranges are too strong and we have to fodl to a 5bet.
Flop: Pretty certain pio raise some of the time for value and protection vs 1/3 and sometimes vs 1/2 pot. I think raising though makes turn and river play tricky to navigate so down with a suboptimal call, unless you study this spot a lot.
Turn: I would protection bet a lot for 1/3 we deny equity from over cards prevent river bluffs. Checking seems fine though.
River: Never a bluff, easy fold. Maybe at 500nl it's a call because they actually balance this bet size.

Against a good aggressive reg you can just 4B get it in here, flatting is also fine but I prefer the 4B because of equity denial, rake and also I just generally prefer putting pressure on people rather than playing passively.

Flop raise or call is fine, raises for value typically want to be more of these middling hands that benefit a lot from protection rather than stuff like sets which doesn't benefit from equity denial. If the SPR is deeper this flips back around against and you start primarily raising with your nutted hands.

Turn I think is a very misplayed spot at these stakes, betting frequencies tend to be way too high when you have a fairly significant nuts and equity advantage so I'd lean towards just betting because I think most villains lack the discipline to check flushes. Also when your range is protected by flushes and sets villain can't really look to go too crazy looking to raise you off of your more middling hands like this without stacking themselves regularly so I prefer to just keep myself uncapped here.

River I don't think you need to call by any means but I wouldn't mind a hero, I think way too many single diamond hands will get bluffed by villain on the turn so their range here is pretty bluff heavy imo, obviously it's fine to let this go but I do think this could be a nice spot to call off pretty light.

Both options are fine preflop I think, TT is more of a pure call and QQ is more of a pure raise, JJ is in between.

I tend to not have a raising range in these situations in general, but if we ever raised something, JJ would probably be one of the better hands to do it with given the amount of protection there is to have. I would guess that equilibrium raising frequency is fairly low but contains some AT/JJ type of hands coupled with some flushdraws and tiny number of other things maybe.

Turn is close between two options again. Betting is fine but the sizing should probably be small, the idea is to get protection and also block.

River is again probably a mixed strategy in theory, I think most people fold these too quickly.

OOP 3BP B-X-B lines by regs in the blinds vs BU formation are significantly overbuffed on:

1) Paired boards
2) River overcard
3) River Ace
4) 4 card straight rivers
5) 4 card flush rivers

You can profitably call with 2nd pair+

All river bet sizes are ovberbluffed from 0.25% to 0.8% of pot which is when they start to become balanced