So far the most important player they lost is Kim, another one but less important is Pegtana.
Napoli transfers in and out in 2023 summer. They must keep Osimhen and Kravatskhelia to maintain their strength at least in their front line. Between Osimhen and Kravatskhelia, they have more risk to lose the Nigerian striker.
Osimhen and Kravatskhelia must survive next season because they are important players up front. Napoli needs to keep these two players from leaving for other clubs because many clubs are trying to influence Osimhen to leave and even big offers always come for him.
In the last summer, Napoli faced a similar problem when they sold Koulibaly to Chelsea but they unfortunately and successfully replace him by Kim Min-Jae. This summer, they lost Kim and will they succeed to replace Kim is unknown. I don't believe luckiness will stay with any club forever. Must mention that they successfully replaced Insigne by Kravatskhelia in the last summer too.
Still a little doubtful whether the loss of Kim Min-Jae can be maximized by Napoli by replacing other players for next season, because Napoli also changed coaches from Luciano Spalletti to Rudi Garcia. It will be very difficult to have luck simultaneously in several seasons and there are many factors that make it difficult for Napoli to defend the previous title for next season.