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.
Playing in the Bundesliga and playing in the champions league are two different competitions and every team approaches each competition they’re participating in differently. Just because Bayern Leverkusen won the Bundesliga title and got qualified for the champions league, that doesn’t mean those same players will be able to win the champions league competition with the same strategy, they are two different competitions with the champions league more fierce than the Bundesliga, so they won’t get to win it easier if they’d won the Bundesliga so easily for them.
As for PSG, if they were able to win the champions league trophy with this same players they have currently in the squad, they can just put more efforts in the champions league next season and dominate it once again if they manage the players well once again. The champions league is the highest flight competition in Europe. So if they’d won it the last, they can still win it again with good approach. Real Madrid have won it back to back before, so I don’t see why PSG can’t win it also, even without signing new players to the club.
Bundesliga and UCL are night and day, and Leverkusen proved it. They finished 2nd in Germany (which isn’t even their best league finish!) but crashed out of the Champions League in the Round of 16. Possession stats and pretty passing (like that 62% possession vs Dortmund) don’t mean much if you can’t finish off elite opposition or your defense can’t handle the clinical quality you get in Europe. Losing Wirtz and Xabi Alonso this summer? That’s their footballing brain and soul gone in one window. If anything, this Leverkusen squad is primed for a reality check in Europe, especially with a rookie manager coming in and a new tactical system about to be installed
PSG won the treble, but that is not business as usual. People get caught up in that Real Madrid three-peat fairytale, but even they made small, key squad tweaks every year, kept the hunger alive, and had a core with insane mental durability. PSG’s doing the opposite: zero real transfers in, riding their luck that the same starting XI can go again after a physically brutal calendar. Dembélé, Barcola, Zaïre-Emery… all ran into the red last season, and the Club World Cup squeezed out the only rest they might’ve had. So, sure, they “can” win it again, but the probability says otherwise. One or two key injuries or a dip in intensity, and the house of cards falls quick. No team in history has stood still and dominated. Even Real refreshed just enough