Even though Chelsea squad is very young and lacks UEFA Champions League experience, that's not enough reason to write them off in winning the UEFA Champions League trophy next season. Football is now full of surprises; nobody believed PSG would win the UEFA Champions League trophy and Chelsea would win the Club World Cup trophy. I believe Chelsea has a big chance of winning the UEFA Champions League trophy next season if they are consistent in winning their matches in the UEFA Champions League competition next season.
It's too early to say who will be crowned champions or who will potentially compete for the Champions League title. Anything can happen, especially considering that PSG and Chelsea have already won the Champions League and Club World Cup, respectively. This doesn't guarantee similar success next season. Although they have won the title, that doesn't mean we shouldn't forget about other big teams like Liverpool, Arsenal, and others, who they believe also have the chance and potential to compete for the title with their new strategies and squads. We'll see how things develop once the competition starts and see if there are any other surprises.
Yes, winning UCL back to back is a very unique and rare thing. Let me put it this way, for the past 30+ years, the only team that won back to back was Real Madrid, who did win 3 times in a row, but that is it, nobody else had 2 titles in a row. When you consider that, do you really think no team was good enough to win? Of course there were teams that were better than others and still lost.
So because we have a historical data that shows that for the past 30+ years only one team did it once, I doubt PSG will be able to replicate that, and most likely it would be like the other 90%+ of the finals where they will not win. Lets see if we are right or not, but it is obvious that we are going to see these things change, and maybe it would make more sense for them to get a better result.