I think simple 15... hg2 was better, there was no need to rush into simplifications with f5. After that again simple moves Qd6, Bg5, Nd7 (Na6!?) should be good for Black.

or Qc7 menacing mate on h2; then g3 Nd7 with almost equal game can follow

White is in pretty good shape, since the Black's attack evaporated.

Looks like a solid choice. 20. Qd3 is also good (gets a tempo on Be3, defends h3 if Be3 moves), even 20. a5 a6 looks OK. Best is probably first 20. Qd3, then 21. a5 with threat of 22. a6 if Black does nothing threatening. Ra1 can go to f1 or d1 or just stay put on a1 until it is clear where it belongs.

You could have tried 22. d6, this opens the long diagonal, allows Qd1 access to d5, and takes e7 away from Black Bishop. You do have to be careful about the first rank, since the Rook moved to a3.

Or perhaps 22. Rb3 instead, hitting b7. Then, if ...b6, 23. d6 could be played with tempo since the Ra8 is hit. Black's king is never going to be safe after this...

Not really   but everybody does things like that, even GMs. You played pretty good IMHO, but maybe overcomplicated things.