He seems like the type to enjoy being more powerful than his omega, so I can see why his type isn’t buff bottoms. Or maybe he has no type but that could just be my bias talking (I switch my preference for twink and buff bottoms on a weekly basis).
However, I wouldn’t have mind if he was with a buff partner, I just hope the blue haired future partner is someone who won’t play by his rules.
I don’t want old man to overpower him! Power bottom if no buff bottom. And I agree! Buff omegas are peak, they have more power to fight back realistically (of course the pheremones will still affect).

Here are the pictures of the alleged partner (said to be on Twitter but I do not know the user of author):
https://imgur.com/a/DwEeZW8
I fear I will not focus much on the main couple, it just seems like another aang type of trope but less of a scary male lead. I have always been a fan of age gaps, as you can probably tell by my profile picture of Xie Lian from Tian Guan Ci Fu.
I enjoy older partner and younger partner tropes more. The old man in chapter 3 will have his own partner, and he looks really cute and pretty! And I hope the old man does not prey on omegas like that anymore, his thoughts were quite disgusting about the omegas.
Just because they have no collar does not mean they should prey on them. Perhaps I’ll understand him when there are more chapters out.