I see that Arsenal dominated literally everything and I'm not surprised that this was reflected in the score. As for other opponents, there will be a different situation, and so far no one knows who will be stronger. If I were the manager of United, I would at least take care to confidently beat outsiders and average teams, this team is hardly capable of more.
Arsenal dominated the first half, while Manchester United struggled to perform well initially and if we think it for a moment that the controversial offside call by VAR that disallowed a potential 2-2 equalizer for Manchester United was not made, I do not think that Arsenal would have still been able to win the match. And one thing is sure the result proves how competitive the Premier League is but there is still a noticeable gap between Manchester City and other teams in the league.