There is no chance in hell that De Bruyne is available for this game, he hasn't even started training yet, nor running, KDB is still some weeks away from returning to training, and when he does return to training, City will have to be careful with him, he isn't just going to be thrown right back into the action, he would be slowly integrated back into the team to avoid a recurrence of the serious injury he sustained on the first day of the EPL season.
That being said, City have coped very well without KDB, Julian Alvarez has replaced him in that role, and he has done it so well. This is a big game against Liverpool, but City are at home and they are so hard to beat at the Etihad. The first game after an international break can be somewhat tricky, the players need time to find their rhythm again, some might return injured or tired; thus i hope we can still get a cracking game.
If De Bruyne is not available in this match then it will be much more profitable for Liverpool even though Manchester City has a number of other midfielders who are no less good in terms of quality than De Bruyne. But I am sure that De Bruyne's absence could affect the results because facing Liverpool is not the same as facing Chelsea or Manchester United this season. Julian Alvarez has taken a good role in replacing De Bruyne and perhaps Manchester City have a number of other midfielders who are quite competent.
Play in home will also provide an advantage for Manchester City, although in the Premier League this could change, but so far no team has been able to beat Manchester City at the Etihad this season. Liverpool are also in good form in the Premier League and the international break may tire the players a bit, but if the coach can see the opportunities then one of them can exploit the weaknesses.