Pep Guardiola had difficulty finding the right player to replace the injured De Bruyne, so he often rotated one player with another for the same purpose.
City are definitely missing the creativity of Kevin De Bruyne, what he brings to this City side makes him somewhat indispensable, but huge praise must go to Julian Alvarez, he is the player who has replaced KDB in the team, playing behind the striker (Erling Haaland), and he has been doing exceptionally well. I know he is not close to being as creative as KDB, but he is such a wonderful player and he has helped City not to miss KDB as much as they would have if he (Alvarez) wasn't in the team.
Footballers are getting injured quite often these days and it is because of the enormous amount of games they are made to play every season, with little to no break; it is so exhausting, and the people fixing these games have to look into this. These players are also humans and it is not just about the money that the footballing bodies want to make.
Creativity, effort, consistency and precision. His passing is above everyone else's and that can make quite the difference. He really is the engine of the Manchester City game in both directions. Whether they attack or defend, De Bruyne is present at all times and decides whether to speed up the game or be calm in a certain situation. With Gundogan and De Bruyne being gone both at once, this specific kind of character is missing in the team at the moment.