I a gree with you. Napoli played at home but they couldn't maximize their advantage in the first leg. As you said Napoli's game was not that good. But at that time Barcelona's performance was also not good but they managed to get 6 shots on target. They couldn't convert several opportunities into goals. But it will be different in the second leg because they play as hosts. Barcelona can also learn from the draw in the first leg. I bet Barcelona will win and will qualify for the next round.
In fact, both teams could have learned from the first leg to make a better game in the second leg, but because Barcelona was playing at home. Of course Barcelona is more favored in the second leg, but everyone also needs to see what improvements Barcelona can bring in the second leg because Napoli also has the capital to be superior in the second leg so Barcelona must be more careful in the second leg if they want to qualify for the next round.
Regarding Napoli who failed to maximize the first leg because they played at home, for me that was a normal result and there was no oddity whatsoever. Because after all, a draw is still a good result for Napoli because yes, in the predictions at least Napoli is quite doubtful and is predicted to lose . But yes, in reality Napoli managed to score an equalizer after conceding first in the 60th minute and in this way, Napoli managed to get a good result in this match. Because yes, considering Napoli's quality and performance at this moment, I don't think there is a good chance for Napoli and I am sure that Barcelona will still qualify anyway.