I admit that Ramos is the perfect defender for the defense of a club, but for now, I am a little doubtful that he will be able to play optimally for PSG, apart from his old age, of course the injury that has been received by Ramos has made his performance will decrease from day to day, as a defender performance in guarding the defense is important and now ramos no longer has that, in fact I believe that ramos will spend more time injured with PSG this season than he has played.
I would say that, at his age he is not really a game changer if you ask me. As a player in the locker room and leading then he is good, he will definitely have a "psychological" help to the team, which is not why they are paying him at all, definitely paying him to play, but constantly postponing his return shows that they are really not in a rush to get him neither, they are fine without him and with him the difference will not be huge.
It is not like Messi, he actually does have a huge change and help, proven by the last two champions league games, but I have to say that Ramos will not make that kind of change. Which is why I believe that there is a good case for Ramos to be a veteran presence that helps the team psychologically more than it helps the team right now. Hopefully he will come back and play awesome, but I doubt that would be the case.