Preflop and XR sizng look good to me (could go slightly bigger maybe).
I dont think that the 6d is that important. There is basically no real combo that 3bets this position and contains the 6d.
But i think i prefer flatting the 3 bet OTF.
A flop 3bet usually indicates a very polarized range, esp as we wont XR merged in this spot i assume.
So if villain reps basically nuts (2p/sets/monaterdraws) or air.
So our blockers to the nutregion become important: there is 1 combo of 67s and 3 of a lower set and maybe 2 straightflushdraws (pair+NFD is blocked).
So our blockers dictate a super small valuerange in Villains shoes what makes the probability of pure air(or 77)a lot higher.
So i prefer flatting the 3bet and playing cautiously on diamonds or cards that improve mostly Gutshots as these are good candidates for 3bet-bluffing the flop.
On blank runouts im still looking to get this in, which should not be too much of a problem given the spr.

His only set here is 77 (doubt pool is really 3 betting 22 vs UTG often). Rest of his range is strong suited broadways (some of which have a FD), AKo/AQo and overpairs.

I would x/r bigger and if I do make an aggressive move after we get bet/3b, I would likely just jam it in. I know we are deep but that sizing that we 4b is just super nutted. The jam looks more bluffy an will probably get called by any overpair with a diamond since he will block the myriad of FD's/SD's you have that can semi bluff here.