Both Osimhen and Kane are good for Madrid job but I feel that Real Madrid should align more with the younger one. They already have issues replacing Benzema. When they get Kane, they might likely have same issues with replacing Kane after about 2 seasons or more.
But with Victor Osimhen, they will have a longer run. But another consideration why Kane will be better is because of his age and experience. His presence in the middle of Madrid attack will perfectly full the role of Benzema. Vinicius and Rodrygo will not have any reason to contest with Kane but they can easily do with Osimhen.
Real Madrid seems to give up for signing Harry Kane, he is over price. What I know that Tottenham wants £200m for Harry Kane price, it is a non sense price for a striker that is almost 30 years old. Real Madrid probably focuses on signing Mbappe, he is rumored to leave PSG because he refuses a contract extension. Mbappe price may be about £180m - £200m, it is not so different with Kane's price. In this matter, Real Madrid absolutely will prefer to sign Mbappe.
Regarding Osimhen, I still don't hear about the issue that Real Madrid wants to make an offer for him. I agree that Osimhen is a strong striker that deserves to replace Benzema's role. But Real Madrid seems to choose Mbappe if it is possible to sign Mbappe.