It looks like Napoli will keep Kvaratskhelia rather than Victor Osimhen, because there is news that Napoli is offering Kvaratskhelia a contract renewal and it seems Kvaratskhelia is also willing to do so, and he even wants all the processes to be finalized before Euro 2024.
If from the business perspective, it would be better if Napoli preferred to sell Osimhen because his market value is currently high. Meanwhile, they should keep Kvaratskhelia because he is still young and has good potential to become a big player which will certainly give Napoli another big advantage if his market value rises.
If Napoli wants to build a stronger squad next season, they can use the money from the sale of Victor Osimhen because his market value is still quite high compared to several other players owned by Napoli. The proceeds from the sale of Victor Osimhen can be used to buy several other players as an option to cover several positions that are considered still quite weak.
Kvaratskhelia is still very young and he has potential in the future if the coach can develop his potential then the selling value will increase. Napoli need some other players for next season and if they don't buy other players and rely on the existing players then it will be difficult for them to compete next season.