You bet enough that all PPs in his range will call. I mean, seriously, no offense OP but I think this is a case of MUBS.

IF villain is tricky to raise 77 or 6-7 preflop and call your 3bet, he should be creaming his pants to value bluff raise your flop bet..since you can't possibly call his flop raise in this spot as all sorts of better hands are in his range.
Playing passive poker with a hand like 6-7 or 77 on this kind of a flop is just not going to be winning poker...does villain see this? or is a passive weak player?

Villain flat calling you on two streets is way more likely to be an overpair with an occasional set. You're leaving money on the table not betting this river

How is this first part tricky? Just curious why raising these hands is considered tricky, and also curious why he would ''value bluff raise'' his draw when he's 200BB deep, are we really looking to get it in with a draw 200BB deep?

Apart from this I think I've got my answer and would like to thank you all.

Results:

oh, i see the later post. you shouldve edited your original post.

I didnt mean the bet sizing was bad, I was saying the bet sizing was not as strong if the pot was 72. if you repopped to 24, then I'd probably 3B to 30ish, but that's just mostly nitpicking. well played, shove river.

i never shove the river. Its between a small value bet to get TT+ to call, or just check folding, depending on how he plays.

Villain would have to be drooling for a shove to get value ( ie, get called and win > 50%).