... but it turned out that while my idea was correct, I actually missed the best move. What lurks in the position?

Hmm ...

Qxf6+ sure looks crushing

7783755
It is. It's mate in two whatever black does (if exf6 then Rxe8# and if Kg8, then Qg7#).

I missed it and played Nxe7 with the idea that Rxe7 is met with Qxf6+ and then Rg7 doesn't work because of Re8#. My opponent after a long think played Ng8, but it doesn't work due to Nxg6+, hxg6, and Rxe8 after which I forced a queen trade and won the endgame.

One suggestion is when you get in a position such as this and you have plenty of time on your clock ... just run through the various forcing moves. Frequently you will find a pleasant combo you did not see the first time.

7783777
Indeed. After all, the principles that make both lines work are similar (weak backrank, queen check on f6, e7 pawn being weak/pinned, threat of Rxe8...

7783741

What about Qxf6+? If pawn takes, Rxe8 mate, If Kg8, Qg7 mate.

7783741
What was your idea because the first move I'm seeing is Qxf6+

Edit: nvm, saw what you did in another comment