Napoli certainly has a good chance of winning the Scudetto again, let's say that of all the teams they are the one with the greatest probability of winning, if you think about it carefully. After a solid year, he continues with a strengthened team and the same coach, therefore they can win again
Since Napoli keeps improving their squad, I also agree Napoli will be the candidate to win the Serie A trophy again for the next season. It is rumored they will plan to sign some top players. Darwin Núñez, Jadon Sancho, Rasmus Højlund, Alejandro Garnacho, Jack Grealish, Federico Chiesa, Jonathan David, and many other players. If Napoli succeed to sign some of those players, their attacking will be stronger.
Reference: https://www.transfermarkt.com/ssc-napoli/geruechte/verein/6195Napoli doesn't look like the only team interested in Jack Grealish. Leverkusen is also after him according to recent news. But I think Napoli option would attract him more. He'd reunite with De Bruyne too.

There are 4 teams interested in signing Jack Grealish. Besides Napoli, there are Leverkusen, Everton, and Newcastle United. According to transfermarkt, Everton has the biggest chance. But if Jack Grealish wants a better career and wins another trophy, joining Napoli looks the best choice. Yes, he will reunited with De Bruyne if he moves to Napoli.
Reference: https://www.transfermarkt.com/jack-grealish/profil/spieler/203460