Last season and the 2 seasons before that they have improved a lot and those were some of their best seasons under Arteta. Their squad this season is still the same as last season. They just need to maintain consistency in every game. Arsenal's squad last season was very worthy of being champions and they deserved it. Unfortunately City were more consistent than them and managed to get a lot of points in crucial games.
Looking at the Arsenal squad right now, I don't think there's any significant change in players when compared to what we saw last season so it's absolutely possible that they might also not beat Manchester City to the league title. However, I feel the manager have taken a hold decision in the top 9 striker's position of the club. Considering his selection in their first league game of the season, it's now obvious that Kai Havertz is now the club's first choice striker which wasn't what we saw at the start of last season. I think Havertz will contribute more number of goals than anyone in the team this season especially converting the goals. Arsenal without doubt will challenge Manchester City but winning the league ahead of City will be a very difficult task
Arsenal, Liverpool, Manchester United and Manchester City are in good shape in this season with their squads. And since thru are doing well in the new season then there is no need for new players to come in. Kai Havertz is good in the midfield and Havertz is also good so the team is gallant now