I can see that it may not be as easy as winning ligue one of course, but it shouldn't be this hard neither. They have been trying for the last 5 or so years to win it, and they have spent so much money and got so many great players and none of that helped them, they always lost.
Yes, they have really tried with the various efforts they have made so far. Even with their financial condition not being a problem, they have brought in many star players in the past few seasons. But in the end, it turned out that it didn't work, because they seemed to only focus on the front line. Meanwhile, football does not only depend on the attacking line because after all, all lines must be truly ready. And one more thing, the competition is very tight within the club itself and sometimes it's not good enough.
But yes, at least, PSG is still trying in that way. Even though now they only have Mbappe as their most talented main player. In the UCL, they will have to face Barcelona, where they should also have a chance, because Barcelona is currently not in their best position. However, it's just a matter of how they can make good use of this opportunity.