Arima-san wa Omega ni Naritai

Nijo Arima is an Alpha who works at a first-class company. At night, he pretends to be an omega and his service specializes in serving customers at night. He wants to be an omega at least for a moment; then, when he meets a young famous student entrepreneur, who is arrogant, and throws words that pierced Arima's heart, Arima is in shock and has a one-night-stand with him without knowing that his fate was sealed.

(Source: Houbunsha, translated)

Note: Includes an extra.