Having this game as a deciding game for both teams has to be one reason why this game is going to be really tough and possibly interesting because both teams will be aiming to win but then win and they cant win together as one team has gat to win as against the other, Manchester City has been of a very poor performance and we all know but i still wouldn't use that as a reason to think that PSG was going to be the winner in this game, the most likely score I'm even expecting from PSG would be a draw and a win possible Win for Manchester City, Pep has always got his way around games like this and i don't see him loosing this particular one.
Yes. This will be a life and death match for both teams because winning this match will give them hope of qualifying for the play-offs and the loser will most likely not be able to advance to the next round. So this match is not only tough and interesting, but this match will also be a proving ground for both coaches between Pep Guardiola and Enrique.
However, I see Pep Guardiola's mentality is not as strong as Mourinho or Antonio Conte. Pep is used to the best team, with the best funds and the best position. However, when he experiences consecutive defeats, he is not ready and his mentality is chaotic.
So I am very sure that in this match PSG will continue Pep Guardiola's slump with Man City. Indeed, as you said, the UCL league schedule is still long so there is still time to build the squad again. However, seeing Man City's declining mentality and confidence, I doubt Pep Guardiola will be able to get through this match with a win. This season has been a bad season for Pep Guardiola as a coach, in fact, it was the first time in his coaching career that he experienced consecutive defeats and I think this will continue.