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.
Actually on the contrary with or without Kevin de Bruyne Manchester City will always maintain there performance, I'm not saying that Kevin de Bruyne is not an important player for Manchester City but however when he had the injury it affected the club seriously bad that it took them time to come back and to strategize that made them cover the role Kevin de Bruyne plays, so right now Manchester City are not much affected because they are already handling the role very well so if Kevin de Bruyne plays the match it will be an added advantage for them but if he doesn't Manchester City will still play the way they normally play.
This is surely going to be a tough match for the both teams because Liverpool is struggling to become the number one on the premier League table by wining Manchester City while on the other hand Manchester City will try all possible best to either win Liverpool or draw in other to still maintain there position.