This variant is distinct from regular chess. Some positions you can win more quickly, and others more slowly. This comes about because stalemate is still a thing.
[title "White to move. (a) mate in 3 moves (b) unroyal: capture king in 2 moves"]
[fen "7k/5P2/8/5K2/8/8/8/8 w - - 0 1"]
(a) 1. Kf6 Kh7 2. f8=R Kh6 3. Rh8#
(b) 1. Kg6 Kg8,Kg7,Kh7 2. fxKg8,KxKg7,KxKh7
[title "White to move. (a) mate in 1 move (b) unroyal: capture king in 3 moves"]
[fen "8/8/8/5N2/K7/8/4p1pp/4Bbrk w - - 0 1"]
(a) 1. Ng3#
(b) 1. Bf2 e1=? 2. Ng3 ~ 3. NxKh1
By the way, does anyone here know a name for this variant of chess where there are no checks or checkmates, and you win by capturing the opponent's king? I'm calling it Unroyal Chess for the purposes of this post. "Checkless chess" is something different. It means that check is illegal unless it ends the game with checkmate.