Manchester United's performance is slowly starting to improve in my opinion and that will have a positive impact on the mentality and confidence of this team going into the next match and what you have to remember is that Manchester United is a big team that has a strong mentality on the UCl stage, so I have no doubts about them can get a win in the match against Copenhagen.
If Manchester United doesn't take advantage of this opportunity and can't win the match against Copenhagen, of course it will be difficult to get through the group, but if they get a win it might give them a small chance to get through the group, even though it will have to be a very hard fight because they have to beat Munich and Galatasaray in the next match with a possible aggregate provides a gap and opportunity to qualify.I don't think that Copenhagen is a club that can be underestimated because they can definitely make it difficult for Manchester United to win, but if they really get up and play consistently they can definitely beat Copenhagen easily, you don't need to win big, just win narrowly 1 - 0 is more than enough, especially when playing at home as hosts, Manchester United must play as hard as possible to get the win if you really have a strong mentality.
A victory against Copenhagen will open up their chances even bigger and they must be able to do it well.