I think it's difficult for Napoli to defend the Scudetto even though they are very ambitious for it. Spalletti's departure is a clear sign that the Partenopei have lost their best instructor.
Osimhen is Napoli's mainstay striker but in my opinion now is the right step for Napoli to sell him because at the moment he still has a fairly high price on the market. It's useless if it is maintained because if Osimhen is unable to maintain his performance next season. I think selling Osimhen was part of an investment move for Napoleon.
Competition will of course look quite tight this season because many clubs might be ready to compete for the scudetto and of course if Napoli sells Osimhen to PSG at a very high price it is clearly profitable for Napoli, at least Napoli can buy some players who have good potential for playing this season, but most of the news says that Osimhen still wants to stay at Napoli.
I don't know if PSG will buy Osimhen from Napoli if yes of course it can replace Messi who has left PSG, I'm sure with the quality of the good front line PSG certainly has the potential to compete in the UCL later, PSG has a lot of money of course he can buy the players they want at high prices even as done by Madrid who can afford to buy players at high prices.