Definitely check out novel instead, plenty to read and there are so many wonderful and important details they skim through. I read here https://borntobenovel.com/novel/diamond-dust
But more groups translating here (you have to have an account to be able to click the links, it's free)
https://www.novelupdates.com/series/diamond-dust/
They seem to be releasing the chapters for free slowly, so no need to pay! But in any case do not pay for any of them (I mean for the groups translating) because these are like machine translations so not so good or 100% accurate. There is unfortunately no official English translations for the novels... So I read what I can find instead( ̄へ ̄)

I'm just guessing, didn't read the novel (I think there's one, pls put the link in the comments, I'm DYING to read it), but I bet the bottom is a diamond omega or something (hence the title), which is even more rare than golden alphas and omegas and he's even more capable to control his peromones (tho unknowingly) and how he respondes to them (every omegaverse is slightly different, so I'm just guessing things and making up theories). OR just has no clue that he's an omega, and everyone told him "yeah, you're just a regular beta". Or just didn't show up his second gender correctly on the check ups.
But I can't wait even tho it'll be on hiatus again in a few chapters. Let's marinate it, bc I just love the art style. I even loved it in Night Song (I freaking knew the art style was familiar)