Even if Galatasaray finds 75 million Euro from somewhere, it would be unrealistic to expect Osimhen to stay in Türkiye when he can play in the Champions League for one of the big teams in the top 5 leagues. He already had offers but he wanted Real Madrid so he was left available this season. If he wants to plan his career correctly, he should go to England or Spain, or go back to Italy. PSG were also interested in him but that interest seems to have passed. Osimhen would normally be moved in the second half of the season but after Icardi's injury, it looks like he will stay. Still, you never know, we might see a transfer at Winter transfer window.
As I said at the beginning, Osimhen was initially going to go to an Arab team, but Napoli got greedy and the Arab team gave up on this transfer.
So Osimhen can stay at Galatasaray.
I don't think he will go during the winter transfer period because he has made many statements that he will stay.
Anyway, we will watch and see what happens.