The UCL round of 16 is sef to kick off next month and for some teams, it's going to be a serious tussle and for some it'll be a minor jump through to the next stage. Judging based on team strength, City has a better chance to advance than Copenhagen, so does PSG, Dortmund and Bayern. For the remaining fixtures, the teams are strong and the result is just unpredictable.
Arsenal and Porto are in good form, same performance range, the probability is shaky, thesame with Napoli and Barcelona. For Madrid and Leipzig, one would say Madrid are in a better position to advance but the German side shouldn't be underrated though, they're also good in their own way. For Inter and Atletico, it's going to be a serious battle, none of them would allow the other to just go freely without making it tough. Hopefully these teams would use their home advantages wisely and to the best of their ability too.
The UEFA Champions League is not for newcomers; the major challengers are experienced and prestigious clubs, and the greatest teams always emerge victors. Does giving Porto to a competitive EPL team seem appropriate? Mikel Arteta has made intentions to settle down and become affluent at elite clubs. Arsenal will qualify for the following round if they can maintain their winning record against their opponents. Checking on the other hand, Porto have become a fierce club, meaning they're competitive rival, Mikel doesn't have to underestimate any club.
I agree with you about newcomers in the Champions League which makes it harder for many new teams in this tournament to bring victory while thinking a team like Real Madrid can have the best chance for the Champions League like they always had. Real Madrid is also trying to improve the team by hiring players like Mbappe or some other superstar player and not just because I'm a fan of Real Madrid but think there are not any other teams on the same level as Real Madrid.