Citty match against PSG will determine if they can survive the group stage. If they fail to win PSG, they are gone. It's only the transfer window that can bring back hope to City because their current players have nothing to offer again for the club. EPL is the only league that City can be hopeful of and that depends on the team's strength after getting new players in January.
Manchester City is a team that has a lot of finances so I am also sure that the team can bring in some new players through the January transfer window. Because Pep and the team management must continue to move to see that option as early as possible in the transfer window because it is true as you said if Manchester City only hopes for a miracle from the players they currently have, of course there will be no significant change in performance for them this season. So the choice must still be able to get new players in order to find changes in their strengths so that they are not immediately eliminated from the UCL this season.
I was not expecting to see this match because between Manchester City and PSG, one team can stay in the tournament and the other team should say goodbye to the Champions League while both are were hoping to win the Champions League. I think now Manchester City can have more chance because of them having Pep Guardiola in this team and his experiacne which is much higher than Enrique's and he has more achievements but to be honest, PSG is much stronger than since Enrique joined this team and now he hopes to beat Manchester City and stay in the Champions League.