It is true that they have built a great wing and striker and even midfield rotation. Definitely looking far better than they are known for, and they are looking stronger than predicted. However, one thing is obvious, their defense is weak and not up to par with their own offensive power.
Jacobs, Abdulerkim Sanchez and whoever is the right wing there, Singo I suppose? That's not really as strong as having Sane, Ilkay, Torriera, Osimhen, Icardi all at once at the front, they are very offense heavy team. When you are the underdogs (and lets face it they are underdogs against many teams) having great offense is not a good move, because you will mostly be defending. I think they will eventually wish they spent all that money on defense, instead of offense.
As the saying goes: the best defense is offense!
Galatasaray have put together an incredibly strong team and with the right strategy and tactics, they have a very good chance of making it through to the next round. It's crazy witch players they have in their squad, a lot of stars who could easily play in the top 3 leagues in Europe for top clubs.
Sanchez, Icardi, Osimhen, Torreira, Sane or Gündogan are really top players and can play dangerously against any team.