After the match against AC Milan in Serie A, Napoli's next big match will be against Juventus & Inter, the rest will only be against mid and bottom teams. after going through all three, Napoli can win matches because they are too superior for them and they can secure the Scudetto this season. Then they can focus on playing in the UCL, we never know but there is a chance for the Italian club to return to the UCL Final and who knows Napoli will make new history this season with the UCL trophy
Napoli will play against AC Milan and Inter Milan at home, this is an advantage for Napoli to get easier more 3 points. While they play against Juventus away, but I also think Napoli won't have difficulty winning against Juventus. So, I assume Napoli will have a small chance to lose points in the remaining matches, except there are too many key players injured.
Considering they are leading with a too big point gap, I agree that they can focus on UCL match. Luckily, in UCL they also play against AC Milan, they must know well how to deal with AC Milan. In theory, they must be in the next round of UCL. And I also believe they have a big chance to go to the final round of UCL. Whether winning the UCL trophy or not, it is hard to predict.