Liverpool can survived without Mohammed Salah in the squad, they play together and the absence of Salah will not pose any threat.
But Liverpool relies heavily on Muhammad Salah to win in most of their games just as Manchester city rely heavily on Kevin De-bruyne to win most of their games as well, taking Salah out of the picture, the absence will really be felt in the Liverpool's future games; However, it doesn't mean that they can't survive without him, but they have to learn to win with or without his presence in the team.
M Salah became Liverpool's mainstay, when Liverpool played without him, they seemed confused when attacking. I am well aware that it is a team game not an individual, but it cannot be denied that the role of one player is a key role for the club's success in playing the strategy instructed by the coach.
You are right when comparing Manchester City without Kelvin de Bruyne, we saw at the beginning of Manchester City playing without KDB they lost the midfield figure who was always the creator of attacks for them. Haaland too, who is accustomed to the mature passes provided by Kelvin de Bruyne, in fact cannot do much when KDB cannot play. Although in the end Manchetser City found a solution, we can see the difference.