This is still a problem and difficult for PSG to avoid because they with the power of star players even when there are Messi, Mbappe and Neymar also cannot promise to celebrate the UCL trophy. So we can conclude that UCL is not about a club full of stars, but about the mentality of all players, teamwork and what usually gives the most plus points is experience many times and understands how the atmosphere of competition in UCL. All of that PSG needs to have if they want to win the UCL, after several attempts until now it has not been fulfilled. Being able to dominate the Domestic League does not guarantee the same thing in the UCL, PSG still has to face teams with different strengths, mentality and cross-domestic clubs.
It is not easy to build a team to be able to win the UCL or compete fiercely with top European teams, as Manchester City only managed to win the UCL after a long process they went through to build the framework or foundation of the team so they could compete in the race for the UCL title.
While PSG currently does not have such criteria even though they have many star players, there is nothing instant in building all teams, everything has to go through a long process and PSG does not carry out that process.