I don't think what you're saying is very realistic. If they don't face one of the tournament favorites, they will go as high as they can. Because we saw in the World Cup that Paris Saint-Germain is competing very well. Everyone who expected the team to decline after losing Mbappé last year looks at this year with surprise and admiration. Expectations are high for them this year. Since they were Champions League champions last year, their fans want this success to be repeated this year.
PSG have won the Champions League for the first time. Not only that, PSG have won the title on every platform they have played on. PSG had their best season in their history this season. And this was possible without any big star players in the squad.
Fans will definitely want to see such a great performance from PSG next season. Dominating the Champions League next season will be difficult, but it is not impossible. Liverpool, Madrid and Barcelona are trying to get stronger. So Luis Enrique should try to take the necessary measures to strengthen the squad.
I can't say that PSG will be able to win the Champions League next season if they maintain their performance because other clubs might have increased the strength of their teams with new signings. PSG haven't signed any player yet, because they feel it's not important which might later become a problem for them next season. This was how Leverkusen thought that they are the best and don't need any additional players when the won Bundesliga title.