Why didn't the Overlords just work with Vox?

Half the season is about how Vox is pretty weak on his own, and relies on support in order to get his way. He's literally already kept back from complete power by the other two Vees, and the only reason why they're not outright disobeying him is because Val loves him and Velvette plans on taking her power back while in Heaven anyway.

If Carmilla, who does genuinely share blame for starting the war, and the other Overlords, simply allied with Vox they could have easily prevented complete control and even kicked him out of the system entirely if they so chose.

We also know that Hell is clearly more powerful than Heaven altogether, considering they needed to do exterminations in order to prevent an uprising and that's Sera's entire arc. It's also during a great time for rebellion, considering their top commander just got killed and they aren't fully prepared for a war against them. Literally just Cannibal town and the Hotel was able to repel the majority of the army, with Adam really being the only one that Morningstar power was used on, along with Alastor support. This war is so winnable dawg.

And for the peace offerings from Hell, yes, as viewers we're aware that they are genuine. But Vox had a VERY valid point during Vox Populi/Vox Dei-- as an oppressed people, we MUST ask who we're talking to? Because Heaven had been down there not four months ago committing genocide and Sera's reaction should serve as MORE than enough evidence that Heaven was prepared to walk back their claims if they make it uncomfortable. Not to mention there was no change of leadership in Heaven whatsoever.

If the Overlords are satisfied with Hell and Heaven being separate, why not dictate terms to Heaven as equals? If the show's point is about redemption and is premised on how choosing death as a point for redemption/no redemption is arbitrary, why not merge the realms and vindicate Lucifer? Why is the megalomania of a singular, relatively weak Overlord somehow the boon of the Hellish Revolution, and why can't his overtake be prevented?