Maybe you should add a third option regarding Osimhen who no longer wants to leave Napoli and because of an injury he has just recovered from.
The third option that you have to add is that it really affects Osimhen's performance on the field so it's natural that he has a decline in performance because there are several reasons why he can't perform like last season and seems like he's just playing without having any confidence because he has to perform carefully. because he didn't want the injury to recur.
Spalletti has a very important role for Napoli, while Napoli was able to reach first place because of Spalletti's help and if perhaps this coach had not been fired, perhaps Napoli could have had greater success and certainly a champions league title this season.
But let's see first how Mazzarri contributes as a new coach, whether he is able to take Napoli to a higher level like when Spalletti was still at the club.