Real Madrid, Man City, Bayern Munich or Liverpool, they are all strong candidates for UCL this season who have the opportunity to win the title and in my opinion Barcelona is the same with its current condition with Hansi Flick, they deserve to be included in the category of strong candidates accompanying the 4 teams.
And to answer your doubts, let's just leave it to Barcelona, especially Hansi Flick, whether he is able to bring Blaugrana further in this competition or not or other possibilities present a trophy, no one knows. For now, let's just enjoy their competition.
So far Barcelona has proven they can be counted upon to be a strong contender for the trophy but the challenge has always been with consistency, the reason they cannot be immediately be given the credit already is because there are still more games ahead for them to prove consistency and in recent season they haven't shown that experience as much as the other teams considered to be top teams and so it's almost very okay to nurse the doubts around them been able to be regarded as a strong contender just yet but I'm optimistic that by mid season of the UCL we can be able to tell better if they will be able to have a chance at the UCL title.