Here are some that I know of
https://www.mangago.me/read-manga/kashikomarimashita_destiny/
-> second couple are the beta and omega
https://www.mangago.me/read-manga/youchina_koi_o_dou_shiyou/
https://www.mangago.me/read-manga/kurui_naku_no_wa_boku_no_ban_beta/
Also, Love Illusion has a betaxomega pairing but that is the third couple and their story is pretty short and it’s almost at the end of the story. But check it out if you want to (●'◡'●)
Can someone recommend me where it's omega x beta, or beta x omega, any category is fine (like, gl, bl, or straight, just any od the three, I'm fine with that)