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