So far Mbappe is a player who has had a big influence on the PSG squad so it is not surprising that there will be a big effect left after Mbappe's departure, but football is not about one player and when a team is left by a player, another player will definitely replace him regardless of status these players, what is happening to PSG now is no different from when Madrid lost Ronaldo and Barcelona lost Messi, but in fact they can slowly let go of their dependence on these two players after new players appeared which they could rely on, that's why Enrique should be able to look for other players to can replace Mbappe next season, even though the player is not a star but he must still have a high scoring instinct and be able to work well in a teams.
We really don't know how a team like PSG will develop next season and in the seasons to come, but what you said is actually enough of an example that a team can still rise with new players recruited by its coach into the squad. And this could also happen to PSG in the coming seasons because the good players are not only Mbappe, but there are also many other seeds that the team can use for this. PSG fans can only hope for the best for PSG next season by no longer having to depend on just one player.