The question is irrelevant. Goku will of course win because he is badly written. He has the Suprerman problem where he is overpowered and over perfect. The reason he's always going to win is because he was written as overpowered and basically flawless from a combat perspective. The reason Guardians would lose is because while they are strong, they were written as able to be killed. It's not because their weapons or their armour sucks, it's because mechanically they need to be weak because they're part of a video game. TL;DR: The question is irrelevant because the two subjects are incomparable.