Defend pre, check flop, and mostly check turn with no draw; river check is fine, but the big turn bluff is unnecessary.
Flop K♠7♠6♦, SB has the nut advantage with Kx and strong draws, while we show up with a lot of air and some draws. Checking range is preferred; with QTs we have no real equity and don’t want to build a big pot against a range that connects well. Checking keeps the pot manageable and lets SB continue with their c-bet range.
Turn 2♥ is a total brick—no flush, no straight, no real improvement for either range. With no draw and only overcards, we should mostly check and sometimes use a small probe. Firing ~2x pot here is too ambitious and leaves us in a tough spot on many rivers, especially when SB continues.
Note: Turn bet is too big and too ambitious with no real equity; checking or using a small probe is higher EV.
River J♥ gives us a missed combo draw (straight + flush) and we’re down to ~1.7 SPR. SB’s range is still strong and we don’t have a credible value hand, so checking and giving up is the best way to realize what little equity we have. Betting would mostly get looked up by better hands and fold out worse, so checking is the right adjustment.