IMO, it seems that PSG will not have a difficult season even without Mbappe in the Ligue 1 competition. because after all they are a strong team that has a depth of players above the average of their competitors, and I have no doubt that Goncalo Ramos or Randal Kolo Muani can be better than the previous season. my speculation is, at least one of these players has adapted very well and played with high performance. besides, if PSG does not have a main striker who can be relied on. Enrique once rotated Marco Asensio as a center forward before he was injured, and his performance was quite good.
Talking about Nico Williams, I would not put him like Mbappe. unless, if Enrique wants Nico to also focus on scoring goals.
I mean this 22-year-old player is more ideal in the winger position, his role can be very central when PSG builds attacks and this player can penetrate the opponent's defense. but, his job is not to be a player who becomes a finisher in the PSG squad. while Mbappe is a player who can play in several positions. even under Luis Enrique he is often played as a center forward, but that does not mean Nico Williams can not do it. it's just that, we often see him operating in the wing sector. related to Barcelona, we have no recent news that links if they have given a proposal to Bilbao. let's assume Nico to PSG, then he can be a good choice for Enrique in his position he plays, his presence can sharpen the Paris Saint-Germain attack line.