I have no problem with Napoli not selling Victor Osimhen to their rivals because they know what Victor Osimhen is capable of doing, and if they sell him to Juventus, Juventus might become a Scudetto contender overnight. Napoli restricting Galatasaray from selling Victor Osimhen to any Serie A club shows that they are mean, and it is not a good sign of sportsmanship.
I need better enlightenment in Victor Osimhen transfer update, is it not a ridiculous restriction not to sell a player you buy to whoever can afford him. My first time hearing this to be part of the contract, if Napoli confirms his worth, why sell him when he can be of use in the club. Galatasaray agreeing to the restriction shows they are truly desperate to sign the player, after paying such amount for the player, they should have full right to do what they want. Nevertheless, if his contract expires in Galatasaray he will have the right to go wherever he wants without control.
Basically, Napoli wants to cash in on Osimhen to get a big profit, as they did previously with kvaratskhelia. However, Napoli maintained their principle of not releasing Osimhen to domestic rivals, fearing that he would have a significant impact, making it difficult for Napoli to retain the Scudetto. At first glance, the anti-Italy clause might seem harsh, but Galatasaray had no objections to the agreement. Napoli also included another clause, they will receive around 10% profit in the future should Galatasaray sell Osimhen to another club.
https://onefootball.com/en/news/osimhen-to-galatasaray-deal-done-eye-watering-fee-and-anti-italy-clause-41402603