There’s no misery in Maldraxxus. It’s the happiest covenant. Maldraxxus is a brutal place, but the people sent there generally like that sort of thing.
Check this whole thread for Maldraxxus wholesomeness.
https://us.forums.blizzard.com/en/wow/t/just-cute-necrolord-things/745933
We have a Void Naaru in the Arena, which is far from a training dummy. I don’t think Calia is super tight with the Void.
What Calia is or isn’t is irrelevant, because her goal is to help the Forsaken, and the Forsaken were raised with Necromancy which came from Maldraxxus.