Liverpool's performance have dropped drastically, Sadio Mane was a key figure in the team and always came through for the team in very difficult game which they are currently lacking a player like that in the team. The absence of other first team players in the team also have an impact on the teams performance but I cannot ignore the fact that it would have been much better if they still had Mane in the team.
Liverpool players are not performing well. Nunez was brought in as a replacement for Sadio Mane, but he has yet to prove his worth. Nunez needs some time to adapt to the Liverpool team, I don't think Liverpool's performance will improve if Nunez doesn't play well. Nunez and Salah will need to perform well if Liverpool is to improve. If this duo doesn't play well, it doesn't look like Liverpool will be able to challenge for the title this season.
No, Liverpool don't depend on Nunez alone. The problem Liverpool is facing at the moment is the storm of injuries that hit their midfielder, the defeat to Manchester United because Liverpool always conceded in their midfield. Even though Nunez and Salah played well, they couldn't do much on the pitch because the supply of the ball from the midfield was very little. Now Liverpool must take advantage of the rest of the midfielders who are still fit, or put one of their attackers in the section to help the flow of the ball to the front line.
I think the problem of low manpower in Liverpool's midfielders is mainly because of their lack of reliable midfielders. If only Klopp, the Liverpool coach has more money to buy more midfielders in the early season. Is it just me or did Liverpool seems to be frugal on the money spent on players' acquisitions this season? Or do other clubs have more money from the sponsors that they outbuy Liverpool?