I also believe that Newcastle can't be a title contender. That is too much for them now. They don't have a qualified squad to make it there. I remember how Chelsea managed to win the Champions League title with Tuchel although their squad quality was worse than teams like Real Madrid, Manchester City.
However Newcastle's squad quality isn't as good as Chelsea's firstly. Secondly they don't have as much experience as Chelsea in this tournament. They aren't as big as them in short. They don't have a mentality that is as strong as Tuchel's Chelsea either now.
Considering all of this the biggest achievement they can get is to qualify for next round in my opinion.
UEFA Champions League is here and there's quite numbers of elite clubs that have good chances of winning it. I've my won favorites, Real Madrid, Manchester City and Bayern Munich. Other clubs would only compete but they will not be able to match the level up energy with these clubs mentioned. We can't compared the situation of Chelsea under Thomas Tuchel, he has solid plans for the club. We shouldn't be having this conversation about Newcastle United winning the UEFA Champions League, it's an impossible mission. We know the competitive teams that would push harder for the league.
As per my prediction I will place these three clubs ahead of the three clubs you have mentioned. Manchester City's opponent in the Champions League final last season was Inter Milan but that is unlikely to happen this season. Bayern Munich, Manchester City and Real Madrid are the three favorites to win the Champions League title this season. Apart from these teams, the clubs that can be tough opponents include Barcelona, Inter Milan, AC Milan, Manchester United. Other teams including PSG may be big names but they won't do well in the Champions League. If Real Madrid had a quality finisher, I would put Real Madrid first in the Champions League.