Bayern should not be compared with Manchester United now, the Red Devils have many internal problems, this affects their results. Galatasaray will not be able to beat Bayern, but it may well score 1-2 goals, because Bayern's defense is not in the best condition right now and they still do not have a reliable goalkeeper in whom they can be confident, but the same goes for Galatasaray, they concede a lot of goals and I think Bayern will be able to score two or more goals.
This is UCL football and alot of things do change about these average teams, watching Galatasaray beating Manchester United was big disgrace. Copenhagen is the only hope for United to grab inother to bounce back to winning ways in UCL. Bayern Munich are topping the group with 6 points on the table, Manchester United are beneath because they have recorded streak defeats in two games played already. It's pressing concerns for the Red Devils because they're elite team and Erik Ten Hag priority to ensured he elevates them to new standards.