Barcelona and Napoli are currently struggling, I think Napoli is way worse. But In the Champions League, teams often find a different level of motivation and performance, and past struggles in domestic leagues might not necessarily carry over to European competitions. Barcelona have legacy and rich in the Champions League, with multiple titles and memorable performances that suggests an ability to rise to the occasion in crucial matches.
Champions League brings out the best in everyone is a crucial point. I think Barcelona is more familiar with this tournament that give them advantage in mentaity aspect. Both Barcelona and Napoli will be hoping to recover before their matches in February. This is the importance of the period leading up to the fixture, where teams can address their issues, regain form, and approach the Champions League clash with renewed confidence.
so far I am not saying that Napoli is a bad team, it's just that the two teams between Barcelona and Napoli have differences and the first difference is that Barcelona experience in the UCL is very big compared to Napoli so Barcelona chances of success in the UCL are superior to Napoli.
however, in terms of players, Napoli has the advantage because in terms of finances Napoli is also better than Barcelona and in this difference I cannot compare which team is strong and which team is bad because both teams have their own advantages and disadvantages.
from my own opinion Barcelona chances of qualifying for the next match are very slim and even Napoli also has a very small chance because as I said above they both have their own advantages but if it is just speculation if Napoli in the 1st match can win more scores because they are playing at home. most likely in the second match, Napoli can qualify because Napoli only needs a few scores to be ahead of the aggregate they have.
but the problem is that Barcelona won't let that happen because I'm sure if Xavi is very smart and knows what he has to do then a draw in the 1st match could possibly happen.