If we are being honest, Liverpool are not in good enough shape to get a fair result against Manchester City right now. Liverpool won Rangers because they needed, they started roughly meanwhile, Manchester is already 90% into the next round so there was no reason for them to risk their key players for the Copenhagen game when they have an important game in the league this weekend.
For obvious reasons, Manchester City are already better prepared to take on Liverpool this week. Haaland has been getting enough rest when Manchester City were held to a draw by Copenhagen. So even though Liverpool may surprise a lot of people with their big win against Rangers, I don't think they are fully prepared against Manchester City.
This big match will be very tiring, so I think Manchester City will take advantage of that match because some of the players have recovered but the rivalry will make it difficult for both teams to win the match. I don't think Liverpool deserve to be underestimated, that's not true even though their performances have not been as consistent as Manchester City's.