We focus so much on one player that we forget that they are a club that has many players in it. Yes, it's natural that when a club has a player who is labeled a "star" then our focus will be shifted to just one player.
Paris Saint Germain's situation is not fine, I will not blame Mbappe, but indeed this situation was created because they took care of this one player too much. The privilege they gave him at the start gave them a headache in the end. That's how we are when a club has good finances, but they can't utilize them.
It would be very difficult to shift attention from a star player in a team, especially when he's the one mostly getting the goals for them, however i get your point because PSG have lots of good players in the club and should be making use of them as well instead of depending on only Mbappé cause there would be a point when it would affect them, for instance when Mbappé decides to leave or is injured, they ought to master the act of performing better without always dependent on Mbappé like they did against Marseille.
The team is good, the squad is balanced but what i think is that they should work on being too dependent on Mbappé even though he's the star player for the team, however Mbappé is still very important for the team and is also needed to help them perform better this season.
No matter how good a player is, eventually sooner or later they will leave, I am reminded of the words "no player is bigger than the club", and what is happening to Paris Saint Germain at the moment is that it seems that their players are bigger than the club, in this case none other than Mbappe. Now will they remain in this situation? I think there must be firmness from management not to focus too much on one player alone.
As you said, they have many good players in the club. I worry if other players start to feel something uncomfortable when they see their teammates being done more special than them. Because new problems will definitely come.
PSG is paying more attention than they should to Mbappe. He is just a player and if they give him more attention than they should, there is the possibility for other players to be unhappy because of giving more attention to Mbappe than other palyer. However we saw this season in some games even without Mbappe, PSG could still win the games. Also, since his players are about to leave at the end of this season, maybe they should start seeking alternatives for this player now.