...and you can't play BxN because of BxB+, losing Ra8, the castling right... a mess for black.

Rd8, o-o seem to be black's best options here, but not a compensation. b4 maybe can help here: Nd5, NxN, BxN, BxNe5!, winning back the piece, or Rd8!, trying to win a piece because of the pin on the Q.

I think I would have preferred this, too, though 14.Nd3 is worth a look. Black might play something like 15...b4 16.Bxb7 bxc3 17.Qf3 cxb2 18.Bc6ch Nd7 19.Rae1 with just about hyperactive piece play for White.

She correctly didn't fall for Nd4, not really dangerous now, but forcing some simplifications that favour white: if the position loses steam, white just wins.

Uff, you have to look hard to Bd4... very complicated!   (Nf4, Qe3...)

After 17. Nc5, Qb5 sets a pin on the Nc5 (Q is behind it, undefended), and a threat on Na4 at the same time. White must defend Na4 by playing (say) Nb3. After it, black goes NxBe3, QxN? Bd4!, winning back the piece (if I don't miss something! ...like Qh6!...) , but the alternative, fxe3, opens the column for the R, but creates a weakness in e3 that can be annoying, e.g. Qc5, ).

I like damalfi's 17.Nc5 here.

You lost the chance to exchange his dsb for your N, helping black to make strong his dsb combined with the b4 pawn.

She kind of lost the chance to save or use her own dsb, like Bc4, or play Nc5, with the idea of Ne6, fxN, Qxe6+ and see if there is "something" with that.

I would have thought "whew, I did it!"

If fxe3, Qa2, followed by Bh6, put some annoying pressure on white, if I see it right.

The Na4 won't be able to stay there forever. But I think that from the moment white managed to take the Ra1 away from its home square, white can think in b3. The WN would be untakable by black, but with a future possible Nb6's threat. So this probably wasn't all that necessary. Very difficult to assess for me.

This Q exchange may yet be White's best, as the only alternative I can see is 22.Nc3.