Alright.
Izuku's only advantage would be initial AP and his Lifting Strength, but Garfiel holds every other advantage.
Garfiel: Scales massively above 283.271 Tons of TNT.
8% Izuku: Scales slightly above 711.97 Tons of TNT.
Garfiel's AD means the stat gap in AP is irrelevant. His range is comparable to Izuku, whose only ranged attack is Air Force. He has no control over Blackwhip in this key.
Garfiel's stamina is greater due to the feats mentioned on his page and his regeneration. Low-Mid regeneration isn't a joke, especially for hand-to-hand fighters.
That means anything sort of fatal attacks aren't going to be effective, and that's out of character for Izuku to do out of the gate. That's assuming he can hit Garfiel.
And from what I'm told about Re:Zero skill level, it means Garfiel is never taking a single hit during this fight? I know intelligence rating by themselves are not all that telling, but Izuku is Gifted while Garfiel is Genius. "He developed a counter to Elsa Granhiert's analytical prediction which allowed her to counter any attacks she had witnessed once before, allowing him to land a blow on her."
Izuku's prediction feats at this point aren't all that special. Not only that, but Garfiel's superior perception holds true, meaning he'll see Izuku's movements in slow motion when he focuses. Not only are his prediction feats better, but he has more time to analysis his opponent due to his faster perception.
Garfiel has Instinctive Action, can deflect attacks, and his Information Analysis will tell him everything about how Izuku fights from the second he sees him.
Not going to call a stomp, since I don't want to argue with anyone, but Garfiel should be taking this fight rather easily, right?
I'm voting Garfiel.