For next season I still favor Napoli and Inter Milan but a little doubtful about Inter Milan regarding the issue of fixed matches. Do you see potential for other teams to catch up to these two teams? in my personal opinion, there aren't any yet, because I use the transfer window as a reference.
For the first few weeks, Juventus, AC Milan, AS Roma and some other contestants will probably be competing closely with Napoli and Inter Milan in the race for the Scudetto. Napoli seems to be stronger among the other contestants because Conte is staying, besides they are also actively adding strength by recruiting experienced players like De Bruyne. However, let's see first how other Serie A contestants complete their plans in the transfer market, as you said, it can be a reference to assess how ready they are all to face the challenges in the next season. Inter Milan don't seem to be as strong as last season, as they have parted ways with Simone Inzaghi.
Napoli is a team with a great reputation and great players, because it often occurs that a strong player is part of your team,making your team stronger by just looking. Conte is a player who's performance speaks louder than his face. So the fans put their hopes even higher that they are with this team due to the presence of a single player. And, i think all the teams in serie A are strong teams but inter milan has my support. Inter milan is a team with consistent performance and a great team as well. I personally believe that now inter milan may face some problems because a coach plays on important role to enhance your performance and to guide all the team members. Now simone Inzaghi who has no need for any introduction will no more participate as coach of inter milan. But i personally think this will create a little bit of problems for inter milan.