For the current Real Madrid team, financially Osimhen might be a very good option but his is very injury prone player. Mbappe is the best stable long-term player but he will drain their budget. I think that Haaland will be the best option for them.
Sure, Haaland is the best striker right now. But whether he can go to Real Madrid. I think Real Madrid must also be ready with a lot of money. But if later Man City is proven for 115 alleged cases, then Haaland and some other players may leave. I think Man City will also release big names to cover the fines. But that's just a prediction. There are no other attacking names at the moment, maybe Serhou Guirassy from Stuttgart is a cheaper option.