That is not true, Man City was defeated by Arsenal just once and it was 10 days ago which is still their first and only match together this season. Maybe you mistook it for the Community Shield game, this happened before the EPL started and can't be counted as part of this season. Everyone has their opinion though, and for me, I will choose Man City over Arsenal multiple times over. My reasons are simple, the team is better and more consistent, only they are not focused for now, this happened last season and they overcame it, the absence of Kevin De Bruyne is another issue right now. This is not peculiar to Man City, clubs do have those moments, the Arsenal time is coming as well when their morale will just drop. I wonder what Man City will do to them to avenge the mere 1-0 win that time.
It cannot be denied that losing several important players last season such as Mahrez and Gundogan had an impact on Haaland performance this season. Of course Kevin de Bruyne is the most important because Haaland's total of 13 goals came from assists created by Kevin de Bruyne.
Currently new players Doku and Kovacik do not have a playing style like Mahrez or Gudogan, who mostly supply Haaland. Therefore, there is transparency in the attack that each builds rather than supplies to Haaland.
Being the top scorer last season, Haaland should be able to show this season as proof that Manchester City still deserves to win the trophy next season. Because if Kevin de Bruyne still can't recover from his injury, I'm not sure Haaland can stand out in every match. In several matches that Haaland played, he did not contribute much.
Like it or not, the defeat against Arsenal was a big lesson in how important the role of the top players that Manchester City had last season was.