What’s wrong with Qd6+?

I was hoping …Qf7 would make the king go to a6. But
…Qb5+ is better because after Ka8, …Qa6.

Line 1: Nxg6.
Line 2: Bxg6.
I thought Line 2 is better because bishop trades knight.
Why is Line 1 better?
Because it turns out that black doesn’t want to give up its rook, so h7 doesn’t take my knight but d7 threatens my queen?

Sacrifice the queen…

Why can’t I do Nb5?

If Rh8+, then …Kxh8, Re8+, …Kh7: This line cannot check the king. Somehow I mistook it with the back rank checkmate…
I need to prepare for checking the king and the opponent’s attack at the same time.

I saw Nd4, but I wasn’t sure how the line would continue. So I chose Qg4. I didn’t see Nf6…😄
The line would only continue with …Qc5.

Not Rf1+ because …Qxd1, Qxd1.