Manchester City can of course feel the absence of De Bruyne in the Champions League as well. However it is the truth on one hand that they are still able to stay strong. Things are going well in the English Premier League these days. They are winning their matches one by one and I don't doubt their performance in the Champions League too.
Manchester City squad is full of talented players. Guardiola can find a solution to his absence one way or another here as well.
De Bruyne is one of the most special players in this squad. He has a wonderful relationship with Haaland. I hope we don't see Haaland getting balls less than before without him. For now he is still doing okay at scoring.
I have always said it and I think it's true right now as well, Manchester City is built like a full squad and one player missing doesn't make them bad. Obviously missing De Bruyne for four months is not that good for them and it will hurt them and that's a very very long period of time, that is true.
However, they will do fine enough at the league if you ask me, they just need to not lose too many games, even if they have to fight for a draw, that's fine most of the time. We are at the start of the season, they could go on a winning rampage when he comes back if they want to, so they could just stay close to top for the time being. UCL is easier because they will be in group stages, in 4 months would we be out of the group stages? Not sure but even if we do, he will be back by quarter finals or so right?