Galatasaray's defense is not very good either. They gave many open positions in the Manchester United match and Hojlund punished the Galatasaray defense with 2 goals. It is certain that it will be a difficult match against Bayern Munich, but Galatasaray needs to get at least 1 point in these 2 difficult matches so that their chances of finishing the group in second place increase.
You're right. Galatasaray already got 4 conceded goals from 2 matches in this group phase. In each match, Galatasaray was conceded 2 goals. It indicates Galatasaray defense is actually rather weak. But their attackers played quite well, they scored 5 goals from 2 early matches. However, when they play against a strong team like Bayern Munich, it won't be easy to be as productive as the previous matches. So, I'm a bit doubtful that Galatasaray attackers will score many goals again. I just think that Galatasaray will be too focused on the defense line. They will play more defensive. It is a chance for Bayern Munich to play more offensively. Considering this matter, I assume the match will end with a draw result or a big win for Bayern Munich. It depends on how strong Galatasaray defenders to stop Bayern attackers.