I have a slightly different opinion than you. I think the Barca and Napoli pair is quite unpredictable; they are the reigning champions of both the Spanish and Italian leagues. Currently, the form of both Barca and Napoli is not good, but when they face each other, the result is hard to predict. Napoli's style of play remains challenging for teams from England and Spain. Therefore, it's not easy for Barca to overcome Napoli in this round.
I predict Napoli can win this match, at least they can draw. Barcelona's problem this season is that their defense is not as strong as last season, their defense is often very chaotic, especially when they lose the ball, this is something that Xavi really needs to fix if he wants to beat Napoli.
I believe there might be a surprise in the PSG and Real Sociedad matchup. Most people rate Real Sociedad lower than PSG, but their form this season has been quite good. I think they are even better than PSG at the moment, not just because they dominate their group with unbeaten performances.
I also believe that among the teams playing in the round of 16, one of the matches that will be a surprise is the match between Real Sociedad vs PSG, and PSG could be defeated by Real Sociedad. Don't underestimate Real Sociedad, because when they are on fire this team plays really crazy, their attacks are very fierce especially when counter-attacking and their defense is also strong. It's just that unfortunately they often go down after the 70+ minute. So it's just a matter of what the Real Sociedad coach will do in this match, if they can be consistent until the end, PSG will definitely be frustrated and can be defeated.