It'll be a disaster for Paris Saint Germaine if for anything Kylian Mbappe leaves for the French capital this season.
They've already lost important players like Sergio Ramos, Lionel Messi and Neymar's future is still uncertain. Mbappe is currently the best player in PSG set up and if he happens to leave at the end of the season, PSG will really struggle come next season
What are you expecting from a club playing in farmer league? I don't think player like Mbappe or Neymar are happy to keep staying, their performance will surely decreased and no have a lot motivation to increase their performance.
Their big matches are on champions league, but as we know they only able to win in group phase and never reach semi final. Accept the fact PSG is a bad club, they only good when they have popular players.
As long as there is money then everything will be fine.
Even though in this case what you say is not wrong, but indeed with money everything can be silent in this regard.
The Champions League is not just an ordinary league because basically the conditions there are much tougher than you think but it's like saying they never made it to the semi-finals is also wrong because if I'm not mistaken in 2020 they've already touched the final it's just that Bayern won and became champions there.
As for the last 2 seasons, I still feel they have had an unlucky season in the knockouts because they always get difficult opponents and even every time they win against PSG, they are the champions and that has happened in the last 2 seasons for Madrida and Manchester City.