We don't know about Napoli's goal for the next season because the way they lost their coach made me think that Napoli wants to also sell some players and make money instead of investing more for the next season.
I think it's not only you who don't know what Napoli's goals are for next season, but there are many other people who also don't know what Napoli's real goals are for next season. But that is also very reasonable because Napoli never disclose their plans before the season starts, although in general the goal for all teams in Serie A is to win again and that includes Napoli.
There would be no point in keeping players such as Osimhen in their team at any cost, no matter how much other teams would be willing to offer, because Napoli knows that Osimhen is an effective player for them.
A good player will always be useful for any team and that also includes Napoli, because the changes made by Napoli are definitely for a better purpose next season because Napoli will also aim to win again in Serie A next season. Although what some see now is as if Napoli will be weak next season.