It's rather so early to say that PSG will find it difficult to qualify because it's just 2 games yet and they won one and lost one so they can still pull out surprises in their next fixtures even though they declined in performance recently but i still see them coming back stronger, they have a very nice squad and Luis Enrique is also keen on making sure that PSG make a good champions league outing this season since they have been making attempt on winning the title for a long time now but couldn't. The UCL fixtures are quite challenging because we can see some smaller clubs showing surprises in this early start so if they maintain same morale it may be difficult for some bigger teams to advance further.
PSG team is still in good shape, I don't know why people are saying that their performance has drooped. When I watched their match against Arsenal in their last champions league game at the Emirate stadium, they really played very well, in fact, they were very serious in the game, just that Arsenal defense is very strong, and Arsenal attackers are hungry for goals, and the PSG defenders were reluctant as the team were playing massive attack and massive defense against Arsenal; I think if the match was against another team, they can easily win the match because they played very well but unfortunately, Arsenal were lucky to use their opportunities well in the game to get two goals because they needed the three points since they played a draw in their first game against Atalanta.
PSG can still make it to the next round because they have potentials in the champions league because I think they will win enough matches to move up in the champions league table ranking.