Truly even Napoli seems to be aware that the drop in his performance is due to the fact that he's not perfectly comfortable playing at Napoli again, so if he goes elsewhere especially Chelsea where he's always seen as his dream team, his performance may likely get back top notch and that will mean he was worth every of the money spent on his transfer and so they have decided to make sure to make as much profit as they can off his transfer so it doesn't appear like they lost at any point. Napoli may not suffer the same fate with PSG in the case of mbappe because osimhen still have an unfinished contract and that's why they kept such a high bid on him.