Inter don't have a very big gap in the standings... Don't forget that Napoli and Atalanta have no matches in the UCL... It's a very big pressure for Inter if they want to beat Bayern or get to the UCL final... But if they make a mistake, Napoli or Atalanta will definitely take that chance to take the lead... It seems to me that in Serie A it is not yet certain who can become the leader...
It is not certain but now Inter Milan are very much favored to win the Scudetto this season after they managed to beat Atalanta last weekend and that also proves that Inter Milan's quality is much better.
Regarding Napoli and Atalanta's undivided focus because both teams are not playing in the Champions League, I think it cannot be used as an excuse because Napoli's performance is quite bad now even though they are only focused on Serie A so it cannot be used as an excuse for big teams to share focus to win several titles.
Yes, it is true that this season Inter Milan is highly favored as one of the teams that will be able to lift the trophy because of their more convincing performance compared to the performance of several other undisciplined teams. The next match in the 30th week, Napoli will face Milan while Inter Milan will face Udinese, so in that match we will see whether Napoli will be able to beat Milan and get full points in the match if in the end they share the same points then I think the difference in points between Napoli and Inter Milan will be even further in the standings because Inter Milan should be able to easily beat Udinese.