Talking about Napoli, basically I'm also not too sure that Napoli will have the same good performance as last season. Therefore, I think top teams like Juventus, Inter, Milan and maybe a few other teams could have the same good chance too if only to predict at the start of the season. Therefore, I personally cannot impose or convict just one team to have the chance to be the best next season. As a matter of fact, we cannot ignore the efforts these teams have put in this transfer window in building up their squads to be even better.
Overall there was not much change in the Napoli squad 90% they use the same squad as last season there is only Min Jae Kim who leaves the club so their strength should still be at the same level unless Napoli release their mainstay player Victor Osimhen then I will delete Napoli from the top 4 list. For Inter and Milan I predict their performance will decrease as we know they have lost some important players whereas Juventus I think will be the strongest competitor for Napoli, I can see Juventus more ready to wade through the new season and Roma in my opinion they will secure the place in Top 4. In addition, some clubs such as Inter and Milan have financial problems generally problems like this have an impact on the team.
For competition in the Champions League, unfortunately we will not see Juventus there this season although they are one of the Serie A teams that can be relied upon, whereas between Inter and Napoli, I favored Napoli to go further. Only personal opinions based on the current squad, predictions can change if some teams bring top players.