How do you know Haaland doesn't want to play together with Mbappe?
As far as I know, there is no any statement from Haaland that indicates rejecting to join the same team with Mbappe. In my own view, there is no problem if these strikers play together. Mbappe can play at many positions, he can play as a left or right winger, not only as a central forward. So, Real Madrid attacking line can be Vinicius-Haaland-Mbappe. This is probably a promising combination and deserves to try by Real Madrid.