Guardiola is Manchester City made a lot of improvements and they have a much better team compared to the last season.
With Guardiola, Manchester City began an era with solid idea on their philosophy from this coach and their transfer strategy changed entirely to support the coach too. Guardiola does not stop to upgrade himself but generally his favorite playing style does not change too much. There are improvements and Manchester City are different than Barcelona with tiki-taka 10 years ago but results are they dominated Premier League and won a first Champions League in their club history.
I think one reason for Arsenal to lose the title to Mcnshter City is Guardiola in this team otherwise they have much better players and good teamwork but that's not enough for a race with a coach like Guardiola because compared to Arteta, Guardiola is much more experienced and when Arteta was assistant coach he was working for Guardiola in Manchester City.
Arsenal and Arteta still have weakness but in last two seasons, especially the last season, they came very nearly to a final win against Manchester City. They failed eventually in a very tight race but I believe they don't give up and are preparing for a better ending this season.
The direct competition between Arteta and Guardiola is very interesting as Arteta learned a lot of things from Guardiola as an assistant coach in Manchester City years ago.
Arteta definitely learned a lot while he was working at Manchester City and with Pep Guardiola but still, these two coaches are not at the same level and I think Guardiola is much better than Arteta which is the main reason why Arsenal lost the title recently however Arteta tried to do his best.
However, I think time after time Arteta is improving and he is getting closer to making Arsenal finally win the Premier League title. They even gave him enough tools and players in Arsenal who can help this coach but it seems it was still not enough for him and he failed so far.