Unfortunately, Napoli is in decline and most likely they will not repeat last year's success, although things can still change. If you remember how many times Inter lost last year, I wouldn’t be surprised if they start losing points here and there again.
As for the Champions League, Napoli are lucky that Union Berlin are also on the decline this season, so neither Real nor Napoli should have any problems qualifying. Braga, I think, can be ignored.
When Napoli former manager Luciano Spalletti left his role as the manager of the club after a successful season with the club which he won the Italian Serie A title for Napoli after over 30 years that they never laid hand on the league trophy which they won back in the 1989/90 season, I was of the opinion that it'll be difficult for a new manager to step in and replicate what he did with the team last season.
The new manager Rudi Garcia without doubt is a good coach but winning the Scudetto in his first season with Napoli will be very difficult for him.
Even if Spalletti had stayed (or any other coach had come), repeating the championship with Napoli would be a very difficult task. Napoli has been one of the big four in Serie A for a long time and is almost as good as Inter, Milan and Juventus in terms of finances and opportunities, but still in this campaign they are eternal underdogs and can take the title either against the backdrop of a decline in the rest or due to a phenomenal series victories like last season. But it’s hard to expect that they can show two such seasons in a row.