I've been at this challenge for some time.

Republic Sovereignty, Elite AI. Can't buy Units AND Bonuses. Placing additional fleets are allowed (to spend accumulated credits). Vehicles are allowed, but it has to be the vehicles assigned to your team (Polis Masa is the only exception). No mods. Pure vanilla. Start must show this conquest highlighted. Time starts once the initial loading screen is done. Each turn and battle must be shown. Ending must show the galaxy is under your control. Time ends when continue is pressed.

Are you allowed to use award weapons?

I'd attempt if award weapons allowed

I don't even think this would be that hard. Just route Polis as early as possible and then it's just a really scuffed GC NBM run