your board doesn't have numbers, but I think knight to the leftmost file is best.
Guess the move :)
Best move is Ne2 +- (3.90) . But Nd5 wins too +/- 1.60) All other are -/+ (-1.00 or more)
variant for Nd5: 1.Nd5 cxd5 2.Bxe5 Bxe5 3.exd5+ Kg7
4.Qe2! (i saw it as i said my comment. Then i calculated black takes Rook on a1 and c3 and thought black king is weak. My friend confirmed me +- (3.90) !!! but only if black finds best defense there...
So best defense after 4.Qe2! is Nf6! 5. Qxe5 Re8 6.Qxe8 Ne8 7.c4 (1.50-1.60)

Augustin, I hope it is OK that I use this forum that you created for a guess-the-move (if not, please delete). If so, find White's move from this 960 game (details: White has not castled but the c-rook has moved, whereas the king and f-rook have not moved):

(By the way, I didn't make the best move and offered a draw after that move. Luckily, my opponent accepted.)

Ok, no one else said anything
So, Qc7 was right. Good board vision, Jack . It is actually not possible to save the dark-square bishop, which was the scariest piece for me (since I had given mine up to win a pawn).
Qc7 is threatening checkmate and the bishop. The f-rook cannot protect stop the checkmate because the d-rook hangs with check. Neither the d-rook nor their queen can stop the checkmate and guard the bishop. Remember the bishop can deliver checkmate (Bb7+). Black's best move is the desperate Rd1+ to get that rook out of danger and gain a tempo.

I offered a draw after that queen move and he accepted. Eval is +2 in his favour even though he is down a pawn.

it took a while (>3 minutes). I thought of the knight check first. Then I noticed the great coordination of the pieces. The bishop is defended (twice). I also realized that your king could take away the only two escape squares of the other king and make the knight check deadly. Your king is safer on g6 than where he currently is and makes the other king less safe. Thanks for these two.
I'll post the answer later.