7 handed, 150/300 live

World-Class player opens UTG, folds to me in BB,
I have 2467 x, I 3-bet (a), UTG calls.

Flop: 1/2

Draw the 8 I bet, Call

Turn (b) 1/1

Draw an Ax, FML, Goes (c) Check/Check

River: 1/1

Draw a 9 (d) Check/Bet/ Easy Call, villain makes K/K (didn't even really see the side cards) chop

Quadruple Blunder Analysis;
(a) Pretty sure I just auto 3! this due to intuition and given a loose game, but may play infinitely better as a call. Wonder if there should be any 3! range v UTG in full ring. Call and D1 is super underrepped, Call and D2 to 742r also possible.

(b) Breaking the roughish 8 (3c7) after the flop also seemed intuitive, but given 3bet pre, and the fact this is the 3rd relevant diamond, this may be a decent pat/semibluff spot, hope villain is still D2, and mucks the turn.

(c) After 1/1 turn, this seems like an easy check. I may be pushing thin equity against a similar type hand, but getting raised is a disaster. After check/check I can breathe

(d) Leading river (now with 4th relevant diamond) seems better; there's no value but I can get better tris to (hopefully) fold, and I'm at little risk of getting raised since i repped a premium draw. However, getting raised is another nuclear disaster in this spot

Any of you draw wizards wanna take a crack at this one? Thanks

Call D2 pre. As played keep the 8d.
I'd probably 3! and D1 if I had 246r7.

3b, d1, pat 8. i think your analysis/questions are good.

Hero range advantage over an utg open is modest, and mostly mitigated by position.

So call d2 and 3! d1 are both good lines, i think its ok to play a mixed strategy. Call d1 is a bit suspect. 3! D2 has merit too but i prefer a slightly better tri.

As played i agree patting the 8 is standard. We have solid showdown value, even when we can't make villain fold.

Xc turn and lead river is fine. Not an easy decision when raised though