Mbappe is a special player. And no one can fill the absence. Mbappe is a much improved player. He is physically and mentally very skilled, strong and he is a successful player. No other player can fill Mbappe's absence. Change is good at PSG. Even though Mbappe is not at PSG, he pushes his team to play well and do something new. One of Enrique's most notable strengths is - he is very nice and fair, efficient in managing PSG's players.
The important change that PSG must make next season is the strength to reach the final in the Champions League and also try to get their first Champions League trophy next season. Because if they are only too busy with the Ligue 1 trophy, I think PSG will still be considered an ordinary team and not better than other teams that have won the trophy. Mbappe's departure to Real Madrid could indeed be a very hard blow for PSG, but that is not the only reason for PSG to remain strong with their other players next season.