Kvaratskhelia's contract is until 2027 so there is no problem about keeping him for a long time. But Osimhen's is ending in 2 years. He might leave for free if Napoli wait for that long. I assume he wouldn't like to end his career at Napoli.
Kvaratskhelia is a young player who is quite talented for the attacking position.
He was successfully brought in by Napoli for a fairly high transfer price and it seems that Napoli will still keep him until the contract expires in 2027 and today marks one year since he has played for Napoli.
During his career in football Kvaratskhelia has also won quite a few titles and this can make him a player with high transfer fees.