If Man City loses to Liverpool, it won't be that big of a difference in points. There are still other matches to chase points. Man City wants to repeat their success last season. I don't think there will be any reason to rest their best squad. at least they will ensure superiority and will replace players to maintain the squad's fitness.
Man City's next few matches will be quite important. they feel they are facing quite strong teams. they have to prepare many fighting strategies.
Every match is crucial in this title race especially the ones they are playing against each other, the match against themselves are the most decisive ones so any club that loses will be short in point. Of course there are other matches that they can chase points from but remember as the league draws to an end every team seem to become serious and teams in the bottom table become difficult to win because they are all fighting for points in order to escape relegation.
I don’t think there would be any need to rest players because players are all trained for such situations of match congestion so they should be able withstand the stress. Liverpool are currently experiencing injury crisis at the moment so it should be easy for Manchester City to capitalize on this opportunity now that most of their key players would not be available. The team now relies on their academy players to survive, the boys have been doing well but they are no match for Manchester City.