In terms of mentality, perhaps Borussia Drtmund in the Champions league does not have great readiness, even in the Bundesliga, Dortmund is unable to appear consistently for reasons that I dont need to mention and we can all know that this club always sell it reliable players so there is no excuse if they fail to compete in the group F because they have to compete with top clubs from other leagues which are much stronger in terms of performance and to compete with Newcastle might be more difficult especially if they have to compete with Paris SG.
I am not saying Borussia dortmund are bad but in reality it too early for dortmund to be able to qualify for the round of 16.
Thing about Dortmund is that they're a big team but they don't really take major competitions very seriously, they just love to qualify for the top four and showcase their younger talents for top club to come them for a huge fee, that's what's been going on in the club for years now and if you noticed they've helped in developing many current top class players including, Haaland and Jude Bellingham not to talk of several other top players in previous times.
In the Bundesliga they're a strong team and on of the threats to Bayern Munich which has been their arch rivals over the years, and though they're not really performing as expected in their past three matches but soon we'll begin to see a turnaround and they'll start performaning brilliantly, whether they'll reach the round of 16 I the Champions League, that I'm not very sure yet, but the group they're in is very tough and the only club that won't really stress them much is Newcastle but I don't think they'll stand a chance against PSG or Acmilan, maybe if they step up but not with this current form.