Bf6+, after the only legal move Kh7, then eventually trade the bishop for the knight? (Black’s bishop is useless since you can just move the rook and king to light squares, eventually forking the king and bishop with your rook. (Idk, the bishop’s continued existence would still deprive you of the zugswang required for a lone rook mate). Or, you could trade your bishop for the knight and then move your king into opposition using only the light squares to deprive black of any forced drawing positions
Rf6+?
You mean Bf6+? That's the correct first move. How do you continue after ...Kh7?
I'm no good at endgames bit but I assume it's...
Bf6 Kh7 Rg7 Kh6 (Kh8 loses to a discovered check) Then the knight is pinned and the black king is stuck on the H file, so the white king can move up and trade down to K R vs. K? You'd just have to make sure you don't get forked by a knight check when moving up.
But that seems too simple so I'm probably missing something.
