It’s actually possible to mate in 2 in this position. Black moves Knight to f3, White has to move King to h1, Black moves Rook to h7 and checkmate.

I’m not actually sure what the “correct” solution is, but mating in 2 is obviously better than mating in 3.

Edit: Ohh I see it. White has to move their Knight to h4 to block Black’s rook on h7. Then black takes the knight on h4 for checkmate.