And this just assuming you match Gundams with a few fighters and carriers with Gamilas destroyers and the like in equal numbers. I think Gamilas is likely to come out on top even then since they seem to have a way better grasp of tactics and dodging is always good. Even with Newtype hax, one guy doesn't solo his way through fleet battles.
If we want to imagine everyone's throwing all they've got into the fight.. pic related is what happens when Gamilas is slightly miffed at you. They drop multiple colonies. Colonies that are actually just bombs. It's not even like this was particularly taxing for them or a big operation; they send one guy out there with the forces to POTENTIALLY do this. It wasn't even a sure thing that he had to. They could have packed this all up and gone home and not worried about it. Blowing up your planet is a walk in the park for Gamilas.
I think Gamilas would curbstomp UC. Even late UC, like F91 or Victory.
I think you could team them up with FC and AC and AD, and they'd still get curb-stomped.
I think you could throw in Turn A and he'd just vaporize half a solar system's worth of the fleet, then move would zip in and slag Turn A.
You don't fuck with Gamilas.