I don’t think that’s nearly enough information to determine a viable winner. If they are nowhere near the same weight class then we know just through physics and fight history across the world that generally the bigger guy has a large advantage in venues where grappling is allowed because they can pull the other person down and lay on them. A big part of learning how to wrestle and grapple is learning a whole myriad of mechanics that are required to not let someone pin you down or gain control over your base.

I almost always suggest women learn Brazilian Jiu-Jitsu and wrestling for self-defense because when they are just tackled from behind, they’ve got the tools necessary to try and extricate themselves.

Also, generally stand up is chaos and there’s always a chance of just getting caught with an elbow to the side of the dome in a scuffle and going down in a heap. It’s always risky to fight which is why you don’t see professional fighters willing to just throw down for no reason on the street.