Only Mbappe is not enough to make a strong team and PSG need more than him to have a strong attacking system and a strong team need more player resources. Asensio and Dembele came as replacements for Messi and Neymar but those players won't contribute too much for PSG proactive defense at their frontline. It is not important in matches with weak opponents but is very important when facing against biggest opponents in Europe. Losing a ball and don't chase opponent players to stop their counter attacking at the frontline, it will cause nightmare for PSG defenders and goalkeepers.
Isn't it true that when there were many star players at PSG, their results in the UCL were not good? So maybe making Mbappe the main center will be easier to manage. The current PSG coach is quite experienced and knows how to sail in the UCL competition. Asensio and Dembele don't need to be substitutes for Messi and Neymar because being themselves and playing with their abilities will be much better. There's no need to burden yourself just because of Messi and Neymar's previous positions. If PSG wants to make changes then the solution is to move on and be confident in their abilities without having to rely on the legacy of Messi or Neymar.
When Lionel Messi was in the PSG team, the coach of the team could not play well by maintaining his positioning. Currently the team is not in the best condition. It remains to be seen how far the team can progress in the Champions League.
Anyway, PSG still has no guarantee to be able to get good results in the Champion League. No matter the current PSG coach and also the current PSG squad because anyway, just to compete well in the domestic league also PSG is still difficult to obtain. Especially in the Champions League, which basically all teams have great efforts to get good results. Therefore, I personally still not sure about PSG in the Champions League, because just relying on Mbappe alone is also a mistake.
Mbappé is a good player, but he is not experienced and mature enough to be the leader to carry PSG to good results in the Champions League. As for coach Luis Enrique, he should focus on the domestic tournament, and then he should continue to dream of the Champion League.
Very few people can solve PSG's difficult problem. Coach Pep Guardiola will have the answer to help PSG win the Champions League. One more coach can do that, and I want to mention that is Zinedine Zidane. PSG's leadership should consider this: even if they bring in stars, they are still puzzle pieces that cannot be put together.