If you look at the strength of the teams in Group A with 3 matches remaining. So United's chances of qualifying for the round of 16 are very difficult. For example, let's say Muechen manages to beat United and Galatasaray, the points are still the same. Then United and Galatasaray managed to beat Coppenhagen. Finally, the deciding match is United vs Galatasaray. If Galatasaray wins or draws, they will qualify. On the other hand, United must use all their strength to win the match against Galatasaray. I think this is the option that comes to mind.
For the Galatasaray match against Bayern Munich if we look on paper we agree that Galatasaray will lose, and as a comparison Manchester United in his last match can also lose because against Bayern Munich, as well as when this fourth match the match between Manchester United vs Copenhagen can get victory then Manchester United will get 6 points, with the meaning of two wins while Galatasaray is only 4 points from one victory and from one draw, and even then if Galatasaray really lost against Bayern Munich.
Now if this scenario occurs then what will be a separate determination match is the Galatasaray vs Manchester United match, this match Ten Hag must bring home 3 full points if he wants to get the density to be able to qualify for the next round from this group phase, but if it fails to beat Galatasaray like The previous match was ensured that Galatasaray was more worthy to be accompanied by Bayern Munich to the next round to continue the league.