White has a very pleasant choice here. Oddly enough, I didn't think of 23.Nd6, but now believe it was the strongest. It seems to win the exchange by force: 23.Nd6 Rb8 24.Rxe5 and there's not much Black can do about the threatened Knight fork at e8, coupled with the masked pin along the (yep!) vulnerable long dark diagonal. I did think of 23.Nxe5; but was especially taken with the possibility of 23.Rd6. It turns out not as good as the other lines, but it does lead to an advantageous ending: 23.Rd6 Rxd6 24.Qxe5ch Qg7 25.Qxg7ch Kxg7 26.Rxd6. More active pieces, a pawn ahead and with a more compact structure.

what happens if black plays 27. Qe7 instead of 27. Qg7?

Not sure off the top of my head... let me see....

After 24...Qe7 (instead of ...Qg7) a simple waiting move like 25.f4 or 25.Kb1 should work.

Here I was looking at 25.Qc4ch Kh8 26.Qxc5 and if 26...Rc7, 27.Qa3. If 25.Qc4ch R6f7 then 26.Rxf8ch Qxf8 27.Nxf7 Qxf7 28.Rd8ch Kg7 29.Qxf7ch!? (29.Qxc5 is probably good enough) 29...Kxf7 30.Rc8 with a winning rook ending. If Black recaptures on f8 with the King (26...Kxf8), a hunt ensues: 27.Rd8ch Ke7 28.Nc6ch Kf6 29.Rd6ch Kg5 30.Qf4ch Kh5 31.Qf3ch Kg5 32.Qg3ch Kh5 33.Qh3ch Kg4 34.f4 Checkmate!

Here, I would have been very tempted at once to exchang down to a pure pawn ending: There are two equivalent ways: [a] 27.Rxf8ch Rxf8 28.Qxg7ch Kxg7 29.Nxf8 Kxf8; or [b] 27.Qxg7ch Kxg7 28.Nxf8 Rxf8 29.Rxf8 Kxf8. The pawn ending is a straightforward win for White: 30.Kc2 Ke7 31.Kc3 Kd6 32.Kc4 Kc6 33.f3. After this, White could have chosen any time to create a passed pawn by e3-e4. It would have been OK next move, though I might be inclined to shuffle the Q-side pawns forward a square before doing so.

Actually, white can play 28.Qxf7 right now. The black Q-side pawns aren't going anywhere, they can be picked up later if black doesn't resign after the Q's and R's are swapped off.

28.Qxf7 leads to the same pawn ending I mention in my previous comment, but with an extra knight for White. After the moves played, the pawn ending is even more favourable, as Black no longer has the c-pawn: 29.Qxf8ch! (let's play to the gallery, shall we?) 29...Rxf8 30. Rxf8ch Qxf8 31.Nxf8 Kxf8 32.b4. Two pawns up and with the majority on both wings, White could have expected Black's resignation anytime soon.

Can I have a point - or two - for 29.Qxf8ch!? After 29.Qd5, 29...Kh8 is a mistake, though the game is, as I've indicated, quite lost for Black. After, say 29...a6 (pick any pawn move), then 30.Qxf7ch exchanges all the pieces (as before) and leads to a winning pawn ending.

10 points... need to work on this lol  

very logical and clear annotations. Well done.