Barcelona in UCL does not have a significant burden because it could be said that group H does not contain strong teams. They can easily qualify from the group phase, but in the future I think Barcelona will have difficulty making progress because Barcelona has many injured players and several players need to restore their rhythm, Barcelona cannot perform much better even in a difficult situation for the squad.
In La Liga, maybe it depends on Real Madrid's consistency. If Real Madrid cannot maintain its consistency then Barcelona has the opportunity to compete for the league championship. We know that in La Liga these two teams will definitely be chasing each other to get points, it's true that La Liga is still long but the habit looks like it will continue.
I think Barcelona are just lucky to be in a less competitive group, facing no threats from teams, rather they keep their high voltage in every match they play in UCL but for La Liga matches, it's definitely going to be a tough struggles for them, losing yesterday in El Clasico against Real Madrid. Barcelona will qualify in their group H because there's no entertaining actions from their opposition. I'm scared Barcelona will not do well this season, having absolutely nothing to offer but due to injured players in the main team. Xavi Hernandez will create path for his team because he's keen on achieving good points on the table.
So far I also can't see that Barcelona raises their game and is then able to compete with teams like Manchester City or Real Madrid in the next rounds. I am not sure yet how Bayern will do, but I think that Barcelona would probably lose against them as well. It is not easy to analyze their game and their weaknesses, but something is missing. I still think that betting on Lewandowksi was a mistake. He is still good enough to score difficult goals, but they need these goals on a weekly basis like Haaland is doing it for Manchester City or Bellingham for Real Madrid and now Kane for Bayern. It is going to be tough against any of these teams and these problems can already be seen in La Liga.