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.
You are right. Barcelona has been eliminated in UCL and Europa League, too. So, we shouldn't talk about their chance to win UCL or Europa League anymore because it is totally impossible for this season. 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.
Yep, Barcelona only has a chance to win La Liga and Copa Del Rey. They are likely to win La Liga title because they are already leading with big point gaps, it is very difficult for Real Madrid to pass/overtake them. While for Copa Del Rey, it depends on the next match, it should be not an easy match.
Well, Barcelona is lucky in La Liga but they are very unlucky in international competitions (UCL & Europa League).