I don't think so. Many teams are still searching for their best form, while PSG have already found their best form, especially after winning the Champions League. Their mentality and confidence have certainly improved dramatically.
For next season, I'm not relying on the team's performance in the Club World Cup. Everything will be different, and some teams will certainly be improving to become even stronger.
The Club World Cup is not a benchmark for teams competing in the Champions League because we can see a number of strong teams losing in this competition. PSG have indeed performed much better after winning the Champions League, but there's no guarantee that they will be able to defend their Champions League title back-to-back. There are still many things to consider to determine who will be a strong contender for next season's Champions League, as all teams are undergoing team overhauls.
But it's possible that PSG are much better than before, so they can perform much more convincingly in the competition, especially considering their performance when they beat Real Madrid in the Club World Cup.