Best move really?

I pin my opponents knight to his queen, and he moved his knight away, capturing my dark squared bishop which revealed attack on his queen, which I took. My opponent was already down a significant amount of material and had a terrible position upon reviewing the game. It said that his move was the best move.. I don't understand how even a tradeof equal material would've benefited him. When all he needed to do was unpin his queen and defend his knight at the same time which at worst would've been a trade of equal material. I'm wondering if you can take a look at the game and either tell me how I'm wrong or make an adjustment to the game analysis because I don't understand how trading 2 bishops for a queen, leaving you with less pawns, a knight, and a rook could possibly be the best move when the opportunity to unpin the queen, and potentially save the knight as well was an option . The only scenario in which that makes sense to sacrifice a queen is to avoid an eminent checkmatate.

[Event "?"]
[Site "Chess.com iPhone"]
[Date "2023.06.20"]
[Round "?"]
[White "macdaddie300"]
[Black "Anxiid"]
[Result "1-0"]
[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
[WhiteElo "910"]
[BlackElo "873"]

1. e4 c6 2. c4 d5 3. Qa4 Bd7 4. c5 e5 5. Nf3 Bxc5 6. Nxe5 Nf6 7. Nxd7 Nxfd7 8. exd5 cxd5 9. Qb5 b6 10. Nc3 Qe7+ 11. Be2 O-O 12. Nxd5 Qe8 13. Nc7 Qc8 14. Nxa8 Ne5 15. O-O Qb7 16. d4 Bxd4 17. Bf4 Bxb2 18. Qxb2 Qxa8 19. Bxe5 Nc6 20. Bf3 Nxe5 21. Bxa8 Nd3 22. Qd2 Rxa8 23. Qxd3 Rf8 24. Rad1 g6 25. Rd2 Kg7 26. Qd4+ Kh6 27. g4 f5 28. Qf4+ Kg7 29. gxf5 Rxf5 30. Rd7+ Rf7 31. Rxf7+ Kg8 32. Rd1 h6 33. Rd8# {1-0}

Check out this #chess game: Jazzsteric vs folarico - https://www.chess.com/live/game/81065515274 why is opponent's pawn to d1 a brilliant

One thing to keep in mind is that engine evaluations that are extremely high or extremely low are not always useful from a human perspective. Stockfish doesn't compare moves, but instead compares the positions that all candidate moves lead to.

The 5 best candidate moves are rated somewhere between +8 and +11, which for Stockfish doesn't make a difference. Stockfish will win (100%) the game whichever move will be played. That makes ranking them harder.

The main move Stockfish is worried about is Bxg7. There is a mate threat after that, but also an attack on the Rook and there still is an attack on the Knight. If black tries to save the Queen, whichever move black plays, the position will be very bad. But even when black plays f6, the position is completely losing.

Feel free to try out all the options black has to unpin the Queen, but I can assure you all of them are losing. Nxe5 is not best because black benefits in any way, it's best because it's the least losing move.

Thanks for the feedback that makes a little bit of sense. I guess his position was worse than I had thought. If it is so bad that even sacrificing a queen, while down so much material is the only hope of saving the game.

Though it is not obvious at first look, d1=Q is a nice move because it draws the bishop away from protecting the king from going to g6 and once the king reaches h8 the position is a draw (even though you can push your pawn to h7) the light-colored bishop can never kick the king off the dark squared h8... Still probably a draw with just kg7 instead of d1=Q so unsure why the move is specifically a brilliant

How does stockfish get a rating # for each player? Not the accuracy rating but the USCF or Elo rating it gives? Do you have the formula?