I feel like there is an overreacting to UCL, it's not an easy cup to win and there shouldn't be a pressure on the players. In any case, Mbappe is very very young, he will still be playing football after Messi and Neymar retires, which means that we could see the owners building a whole team around him yet again and again, maybe get some other known players.
They can only build their team around Mbappe if he is happy in Paris and accept to play for them in next few years or one decade. Since a season beginning, Mbappe does not show he is happy in PSG even receiving so high salary from the club. Depends on PSG results in this season, Mbappe will decide to continue with them or to leave.
Like for example, everyone talks about Jude Bellingham going to premier league as an English player, what if PSG ends up paying him good money to go there? If they can build a team of players age 25 or under, to surround Mbappe with great talent, then even if they don't win now, they can win 5-6 years later with that roster.
In the past, English players did not want to move beyond their country and Premier League to play in other countries at other leagues. Very few English players in the past accepted such risk and had abroad playing journeys. Only few like Steve McManaman (Real Madrid), Gascoinge (Lazio), Owen, Beckham, Woodgate (Real Madrid).
Recent years, we saw more English players moved beyond Premier League especially young players are more keen on Bundesliga to grow their career like Jadon Sancho, Jude Bellingham (Dortmund). Smalling and Tammy Abraham moved to Serie A to revive their career.
However playing in Ligue 1 is not their favorite option at least now. It is interesting assumption that Jude will be a pioneer for English players in Ligue 1. It is possible because PSG is very rich and they can give Jude an irrejectable offer.