I have no doubts on the performance of Bayern Leverkusen even when they participate in the champions league next season. They might not make it to the finals of the competition but I’m sure they will perform well and make it as far as the knockout stage of the competition. Even if they don’t have new players that will join them by next season, I still don’t have any doubts with them, they will still do well. Adding more players will be a bonus to them because of how competitive the champions league competition is as compared to the Bundesliga. Bayern Leverkusen was able to compete and outperform Bayern Munich in the Bundesliga, so they should be able to do as much as Bayern Munich is also doing in the champions league now.
There have been plenty of surprises for average teams in the Champions League and it could end up being much worse next season. Leverkusen is playing well this season and they are unbeaten in all competitions, but I still doubt that next season they can repeat the same thing. The Champions League is much tougher and even clubs with more experienced players will experience defeat when playing. Leverkusen has only been a proven rock this season playing quite consistently but we never know how they will play next season.
If they play like this season in the Champions League then maybe their chances of coming out as champions are a little bigger. But for next season, no one knows how Leverkusen will play as stable and consistent as they do now. Leverkusen need to test their abilities next season in the Champions League and we hope they can play consistently in the competition there.