Galatasaray never cares about one year contract left of Osimhen. They were so obsessed with him, and must get him as soon as they can. I know how stupid them because they may able to sign him for free, but they may be anticipated if there will be also other european big club that approach him once he leave as a free transfer player.
They already have agreemend to buy Osimhen from Napoli. They will pay 40 million first, then 35 million follow next years. Napoli is the winner here.
In my opinion, no, Osimhen is a great player. There were some issues with Napoli that couldn't be repaired, which is why the club and the team decided to let him go. It's clear that a player like that would have done very well at Napoli, but the disagreements meant that there was no continuation.
Of course, Osimhen is a good player and should have contributed a lot to Napoli in future but after the arrival of Conte, he made it known to Osimhen that he wouldn't need his service and removed his name from his list of players. However, Osimhen had already lost interest in playing for Napoli and wanted a new club. Only Osimhen knows the reason why he never wanted to continue playing for Napoli.