I felt for Osimhen when I discovered he eventually ended up in Galatasaray on loan and still didn't believe it until I saw him in the shirt. The Turkish club must have been the least of his expectations, no thanks to Napoli. That is what you pay for being the hero of a club that doesn't deserve you, the key player who helped them win the Seria A title after more than 30 years has suddenly become an abomination to the club, I can't just believe it. No matter what happened, there were ways to resolve matters but it was so obvious with the body language of Antonio Conte that he didn't want him anymore and even made sure that he punished him for not staying in the top-choice European club.
When Mbappe had a fallout with PSG, he was brought back into the team but I don't know how bad Osimhen's case was that Napoli couldn't grant him another chance and reintegrate him back into the team that they had to ship him to Galatasaray. Well, I'm glad he wasn't tempted by the big money offer from Saudi Arabia because he's still at the peak of his career and has so much to offer in europe. He just has to keep his head down, work harder and hopefully, a big club could come knocking after his loan spell at Galatasaray is over.
Mbappe own was different. You should also understand that Mbappe is from France and PSG is his local league. He is also the best player in PSG which everyone knows about it, to abandon him will be like they are killing their own and Mbappe was never too eager to leave PSG then.
Osimhen own is different because he has totally lost interest playing in Napoli and wants to leave the club by all means. He is not from Italy amd that is why Napoli is taking him for granted after he has helped them win the league for the first time in history, if not they would have not made fun of him.