I know Napoli got a rich owner and he can have enough money to make Osimhem stay in Napoli for the next season and since Victor Osimhem is a young player he can easily be sold for a expensive price in the next season if he improves himself. But since there are many tempting offers for Osimhem in the next season from teams like Real Madrid I think Napoli should start seeking an alternative player to replace Osimhem next season, otherwise, they will have problems just like what happened in the game against Ac Milan they failed without Osimhem.
Napoli doesn't have rich owner but this team has a very good management. If you are aware about how napoli doesn't have debt owned by the team. that's why napoli was feeling so good by winning serie a as the fund can be used to make the club even stronger than before.
As far as i know that if napoli doesn't have a lot of money and it's not a rich club.
The 73-year-old has claimed he rejected a massive offer from Saudi Arabia to sell the club,
https://sportsbrief.com/football/37911-aurelio-de-laurentiis-napoli-owner-claims-rejected-eur25bn-offer-buy-club/The owner of napoli has even rejected billions offer from saudi arabia buyers. It's not as rich as you said. Napoli was buying osimhen with very cheap price but he is well developed in the club.
that's why osimhen becomes an asset owner by napoli right now along with kvarat.