It was definitely a good move for Mbappe. No one will disagree that Real Madrid is far ahead of PSG as a club. But we have to accept that Mbappe is unlucky. PSG has not been able to do well in the Champions League in the last few seasons. After Mbappe left the team, PSG has become stronger with the help of Luis Enrique. Now the team is in the Champions League final. On the other hand, Mbappe's team Madrid has been eliminated from the quarter-finals.
If PSG can win the Champions League title, it will be the most embarrassing for Mbappe. But it is an honor for Ligue 1. Everyone insults Ligue 1 as the farmer's league. Because Ligue 1 is not that competitive.

That is sort of like Kane situation, which showed that it was temporary. When Kane moved to Bayern, and they lost it all last year, everyone mocked that Kane was cursed. But look at them this year, they won the Bundesliga. Mbappe had the same thing, first year was bad but I am sure that we are going to see them do a better job later on, it is going to be a better period for him next year when things are moving to a better place.
If we can do that, then that is going to benefit everyone a lot more and will be great for him. PSG didn't get worse because Mbappe left, and that is a good thing, as long as they keep grinding hard and winning then they will build a team that will be good at Europe as well as just France so that is what they want.