GGG always beat Alvarez. Always when normal judges score the fight and he dont have 40 years old. Gennady will be always Alvarez boogyman to his last day. I belive he still wake up at night got nightmares that he must fight him again...
At worst he's 2-1 over Golovkin, that's not a boogeyman lol, that's a conquered foe. As for the Op question, I think the fight would be much harder for him, he'd be far less experienced, and I'm not completely sure he's even ready for middleweight at that point so he could just flat out lose. But I'm of the opinion that GGG was a bit overrated due to not facing much elite comp. We're seeing the same exact script of top guys who haven't fought anyone getting Merc'd when stepping up to face other elite guys. He's not very different in this department. Maybe baby Canelo still beats him...