Galatasaray at home are a very formidable team. They have a very solid fanbase behind them. No matter how good a team is, winning there is never easy. I think they have a chance, even though Barcelona are very good right now, but Gala has a very big chance tomorrow. Even if they don't win, they can get a draw. Barcelona is obviously the favorite, but without Raphinha, their chances have dropped a little. I will go for a GG in that game. I believe there is no way Gala won't score at home, and there is also no way Barcelona won't score. If we talk about a winner, then my money is on Barcelona, but I won't be betting on that. The GG is enough for me.
If you think Galatasaray has a big chance in this match, you're living in a fantasy world. Not even a single Galatasaray fan think they'll be able to get any points in this match. Galatasaray's biggest advantage is that Raphinha isn't playing, but there are still plenty of other stars, If Barca play at full strength, they'll score crazy numbers. But I think they'll play more calmly and with more control since it's an away game. They won't push too hard, they could score 5-6 goals if they need it, but they don't need to so even 1 goal win would be enough for them.
What do you mean by GG, both teams to score? GG means good game, I've never heard someone say GG for both teams to score before. That makes no sense either.