Manchester City lost a match against Arsenal in the Premier League so it is not correct to say that Manchester City has weakened a lot in terms of performance. Sometimes bigger teams lose against smaller teams and this is not unusual. Manchester City's performance this season is a little less than last season, maybe because some important players of Manchester City are injured and they could not play any matches for Manchester City this season, but the reserve footballers that Manchester City have are definitely good player. While Manchester City's performance in the Premier League has been a bit slow, their performance in the Champions League has been normal and they will do well in this Champions League season if they improve their performance gradually.
Manchester City were not being scored many goals last season the way they are being scored this season. Their group in the champions league is a simple group so their reduced performance showing in the premier league will not yet show in the champions league until they play a stronger team in the competition and we will see. Manchester City may not find it easy to win the champions league again this season. Manchester United on the other side of things will have to will their next game in the champions league which is Copenhagen again, if they are to maintain hopes of qualifying from their group.
It's really wrong, manchester city scored less compared to the last season. Haaland itself has made around 12 goals in UCL and 36 goals in EPL to win treble winners. How can you said that if manchester city was not scoring many goals last season compared to the current season?
It doesn't even make sense and you can even try to browse haaland's stats last season and you wiil be seeing that haaland's performance has been declining a lot compare to the last season.
Haaland has not scored a lot of goals this season. It's so easy to get the data about the current stats of manchester city to create a comparison to the stats of city current season. Manchester city's performance was not as good as last seasno caused by it was missing some important players.
I think that you need to take a look at the stats again. It's caused by what you said above was not true at all.
Haaland is still under perform caused by there's no great attacking midfielder that was helping in scoring as many goals as possible like previous season.