Liverpool won't be tired more than City, they will both be tired considering how many injuries each team has and how many games they play, things aren't that easy and because of this we need to consider how to get better results on the long run as well. Fatigue is the biggest reason for injuries, I just hope that we do not see players get injured in this game, not all injuries are results of tackles, most of the injuries are done when someone tries something very normal, nothing out of ordinary, just because they tired themselves out too much.
Hopefully, with this situation being so tiresome, we could finally see UEFA and whatever else competition organizations out there, they can see it's ruining football to have this many games, it means more money when you have more games but it also means that you are tiring the players out a lot more and injuring them and that means we actually watch them less now, back in the day there were less games but players were injured less and we would watch them play more games in total.
It is true that fatigue makes players susceptible to injury, and this is the main challenge generally faced by teams participating in European competitions this season. It is no wonder that previously several European teams criticized the changes in the match format imposed by UEFA, because the majority of them participated in more competitions each season. In addition, key players in almost every club must also strengthen their respective national teams. I agree, the beauty of football in the future will continue to decline, because of the demands of the situation, each club will be purely oriented towards results. Entering the second half of the season, it seems that many managers will complain about the reality they face, and require them to rotate players more than in previous seasons due to fatigue.