This time it is different for Barcelona. The Europa League is going to be very important for them because of their financial condition. They have made many signings and there is even a situation for them like they might not be able to sign new players in January.
Considering this fact, they need to make as much money as possible this season. Maybe they didn't play much good in the Champions League. But I still think that they will fight for the Europa League title. Their priority is of course the La Liga title but I don't expect Xavi to focus on only that. Winning both championships would be awesome for them.
If the management of Barcelona were adequate, then they would not have made all these high-profile transfers in the summer. But they did, and little has changed. What can change if they somehow find the money for the winter transfer campaign? Even winning La Liga and the Europa League won't make them run a budget surplus, and they're heavily indebted.
I don't think Barcelona will add more players to the squad in the winter transfer window. Barcelona is now heavily in debt. Debt repayment is a big challenge for them. Now if they are not making enough money to add more players to the squad. Also, I would say that Barcelona's squad is much stronger now. They have no weakness in attack and midfield. However, the performance of their defenders is a bit weak. However, Barcelona has conceded only 5 goals in La Liga so far. But they conceded goals against renowned and big teams. And their performance in the Champions League was poor only because of poor defense. So Xavi will definitely want to strengthen their defense in the winter transfer.