Actually, in my opinion, pairing Mbappe and Haaland in one team will not be effective, maybe you have seen that with Messi, Nyemar and Mbappe as an illustration that PSG cannot be successful in European competitions. There will be a lot of ego created if 2 players like Mbappe and Haaland join. This is not what Ancelotti wants, Real Madrid stability needs to be maintained, not all great players need to be in Madrid if it ends up destroying the existing balance. Just having Mbappe is enough to complement Real Madrid's front line, and let Haaland remain opposite Mbappe. Because in this modern era of football there is competition for the best candidates in each team. Man City and Real Madrid, keep in mind that if Mbappe and Haaland had to share a place, would that be acceptable to them? The status of a striker is to have his own place as a core player. And I'm sure Mbappe or Haaland are not willing to share playing time.
Come on Mbappe that's enough, there's no need for everyone to be in Madrid, there are still lots of other teams in Europe, don't let the world of football be biased against one team. Because we need competition, not collections.
Haaland and Mbappe cannot play together at Real Madrid, firstly because of ego (no one wants to be in the shadow), and secondly for economic reasons. Real already has 3 of the most expensive players from the top 5. It would be strange to add Haaland here. They all have big salaries so it would be difficult from a financial point of view.
If we talk only about the game, then a scheme where Haaland plays the central striker, Mbappe plays a little lower, and then Vinnie, Bellingham, Rodrigo, then this would be ideal.