How is that better than when they had 7 different 10 goal players last year?
It's just one guy scoring most of the goals other players were scoring anyway.
Now, that in itself doesn't make the team worse. What does that is having less control of games because your press is less effective. There's less likely to be a City attacker on top of the opposition player who just has won the ball, whether that's getting it back or committing a snidey tactical foul before a counter can happen, the lack of which exposes your defence.
There's a reason Arsenal are a good bit clear at the top literally just doing a tribute act to the team City were before Haaland got there.