Their problem is that they haven't found Pique's replacement. Pique is already 35 years old and his physique has declined. Even Pique always has a hard time facing a striker who can run quickly. I think Xavi should start thinking about the central defender. I think he should be brave to start the rotation,for example by installing Kounde as the starting line up. Because Xavi is carrying a mission of improvement and he deserves to give more playing time to the younger defenders.
Playing with young defenders are always a big gamble, all other positions you can fill youngsters but especially central defenders need to be experienced. Major clubs like Barcelona have no luxury to play with inexperienced defenders.
I don't think Barcelona had any chance left in Champions League anyway. They should go to Europa League route and try to win that trophy.
I agree with you. Young players can be given opportunities in attack. Because the young striker is capable of performing well if given sufficient support. But the defense should definitely have an experienced defender. It is very difficult to perform well if the defense is not strong and the defenders are not experienced. Barcelona's defense has been weak since last season. Xavi spent a lot of money to strengthen his attack. He should have strengthened his defense. He didn't do it. And its bad results are quite visible now.