I think next year's top three will be Juventus, Inter, and Napoli. Furthermore, the Italian league is quite competitive. There are strong teams like Fiorentina, Roma, and Lazio. Serie A is a league where every team poses a threat to the other. I'm confident Juventus will finish high because they have good players, and the manager seems to have been a good fit for the team. Juventus had a good momentum towards the end of last year.
Except for Juventus I agree with the Napoli and Inter Milan pick. Inter Milan and Napoli looks very promising, if you are trying to make comparisons between clubs in the Serie A, you will see that the both have good quality and the depth of the squad is very much okay, Inter even has a better prospect between Napoli and Inter, as for Juventus, I will need to wait till mid season to say if I will express the support of a chance for them to possibly win or finish at the top of the table.
I'll rather say Napoli Juventus and Inter Milan, Napoli is my first option cause they won the title and look ready to do it again since the brain behind the trophy Conte is still in the team he wasn't reshuffled to Juventus or Inter. I'm not still convinced about Inter though since i don't trust that their new coach is equal to the task but since they still have most of their players intact I think they'll do well if the coach can manage them properly.