The chances of Napoli winning should not be underestimated either. If they can beat Barcelona, they can become champions.
All teams do have a chance to win the european league including Barcelona and Napoli, Barcelona is indeed a team that european clubs feared before, but not for now, so Napoli must believe that now there is nothing to fear from Barcelona, because Barcelona are in a phase drastic decline in performance, I think for now Napoli are still better than Barcelona so their chances of going to the next round are bigger than Barcelona.
Of course, every team has a chance to win the Europa league. It is a fact that they play well, especially if they have come this far. However, we can make a guess when we look at the performances and the quality of the squad in the matches they played in their league. Especially this year is a successful year for Napoli. Barcelona, on the other hand, is very bad. This year, Napoli could knock out Barcelona. Even if there was this match 5 years ago, then I would have said that Barcelona would have won.