Totsugimasen Kara by Sunako [Eng]

Plot:

Fresh out of high school, Itsuki is sent by his mother to work as a servant for the prestigious Tenmei family. However, he soon discovers that he’s not just there to serve—he’s actually a candidate to become the bride of Tenmei’s young master, Jin!

But the competition is anything but easy. His rivals are all elite Omega from influential families, while he comes from a humble, ordinary background. Can Itsuki stand a chance in this high-stakes battle for Jin’s hand?