I think they're (as always) inversions of each other- Alastor is an extrovert that masquerades as an introvert for self-defense, and Vox is an introvert that masquerades as an extrovert for self-defense.
Alastor likes to pretend he is closed off, cold, and needs no one- but we can see this isn't true. He values his connections greatly (Mimzy, Niffty, even Rosie). Even in the very short montage we see of his human life, they made a point of showing him looking extremely happy, surrounded by friends, being the center of attention playing the piano. That's clearly his most natural state. Yet he feels safer when he keeps others at a distance, because he can't be hurt, and the relationship can't change, if he never looks at it.
Vox, on the other hand, canonically has "no friends outside the Vees", but loves to act like he is Mr. Popular (in his mind I'm sure he conflates 'fans' and 'friends'). I don't think Vox is unhappy by himself or with a very small circle at all. In fact, he often needs to be by himself to calm down and re-center- this is literally what he's doing when he sings "Brighter". But Vox wishes he were a true extrovert, because he feels safer when he has a constant output. He feels like he can control people's perceptions of him if he never gives them a quiet moment to consider him.
Alastor died from a gunshot, and even as a demon he still showed fear when someone aimed at his head. Vox died from electrocution, yet he can still turn himself into electricity and casually electrocute random bystanders without a second thought. Bro's mental is insane.
Vox could literally use his hypnosis to force nearly every sinner in hell to follow him, but instead he chooses to EARN their admiration and loyalty bc he couldn’t stand feeling like their approval is fake, he needs to feel validated and needs that validation to be real
I absolutely adore the fact that the butcher in Costco was blasting Hammer by Point North and when he saw me bopping along he and I started head banging over the chicken thighs. Now that’s pop punk af