Arsenal looks better because the team's progress continues to move in a positive direction, but whether or not they win at the end of the season is not only determined by the team's performance, there are several factors, one of which is mentality and I think that is a strong reason. they cannot become champions because mentally they are no better than Manchester City.
If you look at the progress they are going through, of course for next season Arsenal's performance can be even better, but winning the Premier League title is not easy, this is the most competitive competition.
What you say is correct, a club's performance is not the only factor that can make a club become champions, there are other factors that they must have, one of which is mentality, especially mentality when they face clubs that have the same strength as them or even better than them. In my opinion, luck is also a factor which can make a club win the title.
They must have a good mentality, especially in the competition in the English League, which is certainly not an easy competition. They also have to make sure they have an even squad depth, because they will be in many competitions next season and they will face a very busy schedule, so they have to prepare everything including rotating and it has to be with an equally good squad between the main players and substitute player. The storm of injuries is something they don't know when it will come and they have to prepare for it all amidst a busy schedule.