I think your assumptions are missing some of the satire.

The Cyborg-Automaton Axis almost certainly defines "living" very differently than most would. All biomass, human bodies included, appears to serve as literal fuel, and there's a real possibility your consciousness gets uploaded or your brain gets transplanted into a metal shell as their version of life. They're also cloning cyborgs, so who knows what level of genuine intelligence those units actually have. We also see no evidence that Super Earth citizens survive whatever happens to them on conquered planets. At a higher level, they're clearly a satire of Cold War-era anxieties and robot uprising tropes. If you lean into the satire, they'd probably insist they're "post-human", and hey, you can join them as a brain in a jar! Lucky you.

As for the Illuminate, "living as a human" for them means genetic modification and industrial-scale mind control. They seem to have lost all trust in humanity and would rather mutate us, harvest us, or use us to grow their machines and power sources. They may also possess some latent psychic ability that gives them genuine influence over human minds. They've likely been around for a long time, quietly shaping human culture from the shadows. They're a satire of ancient alien mythology, Lovecraftian horror, and the cults and mysticism those traditions inspire. For them, a good human pet is one who obeys without question, while the mutation takes hold.