If Osimhem is the striker that Real Madrid is targeting then in the previous transfer market Real Madrid will definitely make an offer to Napoli and I'm sure it will be difficult for Napoli to refuse that offer. But in fact, Real Madrid did not make Osimhen their main target and still favored Mbappe as one of their desired targets. Mbappe has much better advantages compared to Haaland because this typical player is much stronger and masters playing positions on the wing or as a central striker.
Any of these strikers will be good for Real Madrid because they are all natural strikers. And they are all young striker that will lift the attacks of the club but I think Real Madrid is focusing on younger strikers. Real Madrid signed these players at the following age Vinicius Junior (18), Eduardo Camavinga (18), Jude Bellingham (20) and Arda Güler (18). I read a news where it was reported that Real Madrid might not sign the French striker because he is now above the age of the players they are targeting. Victor Osimhen and Kylian Mbappé will be the best strikers for Real Madrid because they are aggressive and could make Real attack more dangerous.
Haaland is only able to complete passes to score goals, but speaking of needs I believe Haaland and Mbappe are two figures that Real Madrid really needs. If both of them can be brought in in the next transfer market then I think the Real Madrid squad will be much better and will produce striker who are quite feared by any opponent.
If I were Carlo Ancelotti my best choice would be Kylian Mbappé if Madrid has the money to spend. He is a better striker than the two options but he will be more expensive. He is less injury-prone and is a strong contender for next year's Ballon d'Or. But Victor Osimhen will be cheaper but he is injury prone. His extra-aggressive nature of play exposes him to injuries. He can take greater risks and is stronger than both Haaland and Mbappe.