I’m going to rant a bit but I’ve had this thought for a quite a while and I want to get it out of my system so please bear with me for a moment.
Michio is one of the few characters that I would say has legitimate deep psychological problems, not just "edginess". I'm not going to claim that he is a great well written character, but he's certainly interesting to me.
I think Michio has a very extreme case of dismissive avoidant attachment or something similar. His paranoia is bottomless, when he's not fantasizing about boobs or trying to figure out how exactly his jobs/skills work, he's constantly panicking at the idea of how people are seeing him and not just strangers, but his slaves too.
The reason why he's buying slaves is that it's literally the only option for him. He NEEDS complete control over someone in order to trust them at all. And even as magic bound slaves he can barely trust them, he still tries to manipulate them in getting their “consent” (even though he technically already has it since they are his fucking sex slaves) because at his core he can't fathom someone being truly interested in him, and he only lets down his defenses and kind of tries and connect with them because they are under a slight obligation to do so. He’s a very broken person, and even with his cheats he remains broken.
Roxanne is literally willing to give her life, but even that is not enough for him, he still refuses to let her and Sherry know almost anything about how his cheats works (and thus maintaining complete control) even though he could do so much better in the dungeon if he trusted them more, especially with Sherry's help. Unlike Roxanne who is kind of an obedient meathead, Sherry is quite perceptive and keeps noticing his cheats, in some case figuring out what they do just by looking at him, but every time she asks him how they work he quickly dismisses her or changes the argument without even coming up with an excuse, leaving her confused and bewildered, wondering how this weird guy can pull off such insane advanced stuff yet lacks basic knowledge everyone in that world knows. If only he at least had the decency to come up with some bullshit excuse if he doesn’t want to reveal that he is from another world.
To add to this because the people he's relying on are "his slaves" it also helps him perform the mental gymnastics to continue to believe he is on his own.
Now I’m not sure how much of this was intentional on the author’s part. Maybe I’m just reading too much in this silly wish fulfillment isekai slop (which I enjoy by the way). Just a thought I wanted to share.