PSG are in a transitional phase. I would never call them "a mediocre squad", as I was saying they have a very interesting team, a great manager who knows how to work with young players, and if they give him and the players enough time they may actually make it. It doesn't always work, I remember 20 years ago Arsenal had a beautiful team with a great mix of young and experienced players but unfortunately they never won the Champions League.
You're right. It is totally strange if there are people who say PSG is a mediocre team/squad. Everyone knows that PSG is one of big teams since few years ago. Even, this team ever has Mbappe, Messi, and Neymar together in their squad. Nowadays, they still have many top players in their squad. Donnarumma, Marquinhos, Achraf Hakimi, Lucas Hernández, Khvicha Kvaratskhelia, and Ousmane Dembélé are some of the great players in the world. It is just nonsense if people say they are mediocre. They were just unlucky that they often failed to win UCL in the previous seasons. But in this season, they have a better mentality to compete in UCL. PSG looks stronger after Enrique became the manager/coach of this team. Enrique has won many trophies with Barcelona and PSG. So, it is not surprising if we see PSG to play stronger this season.
It is indeed very strange if someone says that PSG is an ordinary team because in reality, PSG is a team that is able to advance to the quarter-finals and this is certainly extraordinary. Indeed, PSG struggled to advance to the quarter-finals through the play-off round first, but seeing the reality now that PSG can beat Liverpool, it is certainly something extraordinary and of course it is also possible that PSG will become champions this season because until now they still have top players like the ones you mentioned.
Yes, indeed, this season, PSG's mentality seems better and of course this will make it difficult for the team that will be their opponent. Luis Enrique is indeed a professional coach and of course, PSG's game is currently extraordinary and of course he will use all his strength to make PSG win the trophy. But of course, in my opinion, the team that can advance to this stage is certainly an extraordinary team and of course we'll just see what happens later and of course more exciting matches in the UCL will start in the next match.