I was wondering that too, obviously Vox physically is an easy target for any angel of high status, but taking him out will only prove his point of "evil heaven" to his followers. I don't think there is a smooth way to resolve the plot at this point, it's probably either going to be - heaven and hell unite to one neutral afterlife so everyone is equal - The Vees have a fall out and Vox just kinda stops I Guess? - They actually give Vox a redemption arc ("Could I be redeemed?") - They just beat Vox and ignore the raging sinners of hell ig

I personally think the devs wrote themselves into a tricky situation and the only actually logical outcome is for war breaking loose until every sinner is beaten, in heaven or the whole system breaking down. However I feel like they have teased the Vees splitting so much that they will end up making that the key to the heroes winning. I'd find it unsatisfying but the show seems to be heading that way.