The departure of some of the best players means they don't have a similar replacement yet. Gudongan, making the midfield line has no attack creator other than De Bruyne. If Bruyne is injured then Man City are like losing a creative person. I think against Sevilla they lost 2-0, it was difficult for them to win. Unfortunately, several goal-ready chances failed.
Overall Man City played well in the match, but there were no creators to build attacks, making it difficult for Haaland to score goals. If we watched the match, we can see how Man City dominated in that match, Man City successfully made seven shots on target and dominated the midfield. The loss of De Bruyne left the front line unable to do much and there were no players capable of flowing measurable passes to the forwards.
Sevilla's first goal came from Youssef En-Nesyri's header due to an anticipatory mistake made by a defender and fortunately Man City managed to equalize through Palmer, so the match had to continue through Penalties and Man City managed to come out as champions.