Yeah, PSG had a powerful team whether in the attack line or the defence especially in the previous three years, yet they weren't able to obtain UEFA Champions League and they continue to fail to reach the final game.
Luis Enrique already started signing new players and continue persuading others. There is Kvaratskhelia on the list which seems to be close from joining PSG and we all know how good he is with Napoli. There is also rumours about Rodrygo from Real Madrid but it seems that Pep Guardiola wants him in Manchester City too which makes things more complicated for PSG.
Kvaratskhelia could be an option for Mbappe's replacement when he decides to leave this season but for Rodrygo it seems a little difficult.
He is still the center of attention in Madrid even if there will be Mbappe in Madrid but it will not interfere with Rodrygo in terms of position so there will indeed be no problem for this player and will remain in Madrid.
There are some players like Dembele or Asensio who are actually still very good but Enrique still can't bring out their potential especially for Asensio so even if Mbappe eventually leaves if there is Kvaratskhelia in the squad it won't be too bad.
For Ligue 1 actually they will not worry too much because after all Ligue 1 always leaves the first place for PSG but to compete in the Champions League it is at a slightly different level so they have to work extra if they really want to be the best because some big clubs are still quite balanced even better than PSG also want the same results in the Champions League.