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.