Next season Barcelona will have to work harder to be able to compete in the Champions League. Now their problems are not over, but they have to take part in the competition no matter what their current situation is.
If they can't play a good game, then I won't be surprised when they fail in the Champions League next season. Moreover, they are also with a new coach now. I don't mean to underestimate Flick, but he has many limitations from the team he handles.
All European football clubs are part of UEFA and they follow the same rules, UEFA rules.
All big clubs have the same problems, like Financial Fairplay, fan expectations, etc...
Some clubs can solve their problems in one season, while others need more time but There are many reasons why they can be called a big club

So there is no reason to be pessimistic about the current condition of the club, trust the process, Barca has good management and knows exactly what they have to do to return to success at the highest level.
Enjoy the journey. Don't be pessimistic