In the Champions League Barcelona has quite the advantage over the teams that are not that strong in group H, but in La Liga Barcelona is still able to be beaten by its true rivals like yesterday at home so it is appropriate for Barcelona to use young players in their squad without more reliance on aging main players. I also think that in the Champions League this season Barcelona will not run smoothly because there are many strong teams that will be obstacles for him, but in La Liga Barcelona still has the opportunity to make improvements in order to advance to first place this season.
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.
Don't assume like that just yet because in Group H which is considered to be Barcelona the strongest team can actually still be matched with Porto which is team from the Portuguese League and Porto cannot be taken lightly.
Just look at their previous match they were only able to give Barcelona 1 - 0 win and in that match Barcelona looked quite difficult to penetrate Porto defense.
In addition as you have said Barcelona has several players who are injured which will affect the quality of their play in the UCL.
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.
For La Liga itself, I still believe that Real Madrid is superior and it can be proven from their match that Real Madrid is able to beat Barcelona.
For the UCL it also looks like it will be the same where when these two teams qualify for the next round Real Madrid will still be superior to Barcelona.