Yes, Napoli have total problems on all fronts this season, if I may say so. Overall a miracle can happen, but I don't believe in it and moreover Barcelona obviously look better. Yes, both teams have played badly, Barcelona on top of that are unstable in their league, but they should have enough of their skills to go further ahead
This is the fact, Napoli management seems to only see the problem from one side, namely from the perspective of the coach. Therefore, they have changed coaches several times, and will probably evaluate their players when the transfer window opens again. The chances of Napoli beating Barcelona are very, very slim, however of course each club has different luck, and it could be that Napoli advances to the quarter finals, while Barcelona could be eliminated in the round of 16.
Napoli and Barcelona are both unstable in their respective domestic leagues, but it could be said that Napoli has even slumped, because it has been out of the top four in the standings for a long time. In this case, Barcelona is still better than the Serie A representative. The change of coach carried out by Napoli management cannot boost and guarantee an instant increase in performance, everything requires an adaptation process.
Barcelona are more stable in their game, in their league, they go 2 - 3 places, unlike Napoli. Napoli don't seem to have such a bad squad that they need to renew it, so a change of coach is a justified choice for them. But whether it will help them at the moment is doubtful