Real Madrid has been the team to retain the Champions League back to back no doubt but this doesn't mean that other teams will not have the same opportunity to do what they did if they perform well like Real Madrid did he they won the champions League. PSG has shown sign of improvement in their performance and they have quality players to back their performance up I see nothing stopping them from winning the competition for the second time in a roll unless they get injuries or meet an opponent that stops them on the way.
In modern football, winning three Champions League titles in three seasons consecutively is very impressive and it is more impressive as none of other champions manage to defend their titles in a next season. Real Madrid is the only club and champion could do this, not only once but twice and it's impressively in UEFA Champions League history.
With this great history and many players they have now, they certainly want to win this title in this season. Their brightest star player Mbappe left PSG and joined Real Madrid to win Champions League and Ballon d'Or. He would feel very eagerly to win it last season after witnessing Haaland won it in his first season for Manchester City after leaving Dortmund.
This season, Real Madrid will potentially become stronger than last season but it's never easy to win Champions League title with many big clubs around Europe aim at this trophy.