It is very easy for PSG to dominate Ligue 1 and dominate other domestic competencies with the top players they buy every time the transfer window opens, but winning the Champions League is not as easy as buying players. In fact, PSG was only able to advance to the last 16 in the last seven seasons, they reached the final in the 2019/2020 season, then in the following season their progress stopped in the semifinals.
This season the PSG squad is under the guidance of Luis Enrique who has experience in the UCL, but their inconsistent performance makes their journey very difficult when facing big teams. I don't think PSG can surprise this season, they qualified for the round of 16 due to luck after fighting hard in the group stage.
This season's UCL trophy is not for PSG, there are still other strong teams who always perform consistently who are better prepared to fight for the trophy. Luis Enrique must develop a strategy with a more solid team strength if he wants to bring PSG to the UCL trophy.
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.