It's not impossible for Barcelona to win the UCL. But if you talk about UCL for Barcelona, I think it's out of context. Because Barcelona has fallen from the UCL.
It is possible that Barcelona can win LaLiga and the Copa del Rey, both of which are still ongoing. Barcelona is also a strong club, but this season has been unlucky in the UCL. You can say it like that, if Barcelona has never won the UCL.
Indeed, Barcelona's focus right now is on La Liga and also Copa del Rey, because they have no longer been in the Champions League or even in UEFA European League. Their failure to survive in the two big champions is very disappointing and gives Barcelona big lessons. But at least, they are now focusing more on La Liga and Copa, so they may still have a big chance to at least gain a trophy. This is good enough at least, better than the previous season.
This may be different with Real Madrid. In La Liga, they seem like not having a big chance to get the trophy because of the big point difference with Barcelona. This seems like Real Madrid is now more focusing on the Champions League than la Liga. Although they must also still play their best because they can at least be still in runner-up, not under Atletico Madrid.