I don't think so, Spalletti had a good performance in Napoli but most of the results he got and the title he won was because of bad performance in other teams and the dram happened to Juventus otherwise even Spalletti couldn't have had this performance in Napoli. Spalletti knew he can't have the same performance in the next season and I think that's the reason for him to leave Napoli, also we don't know yet if some players like Osimhen will stay in Napoli thats' why I don think Rudi Garcia can have the same performance as we saw from Spalletti.
The most important reason for Spalletti's departure from Napoli is simply the boorish attitude on the part of Aurelio de Laurentiis, whose apotheosis was the extension of the contract with Spalletti by e-mail and that the journalists were the first to find out about it. Also, de Laurentiis didn't bother to just call and congratulate Spalletti after the championship match. Also, do not forget that Napoli was among the leaders last season, so you should not blame everything only on the troubles on the part of other contenders. I think that even de Laurentiis is still sane enough to demand an automatic title with a big advantage from Spaletti next season, so I don't think that Spaletti's fear in this regard could play a decisive role in leaving the post of head coach of the team.