I've just finished reading "After I Got Married, Those Who Slagged Me Was Reborn" by rain falls like dust(?). It's really2 good. We've got a badass omega MC (he takes revenge for his family, hits people who badmouth his Alpha, he's the one persuing/seducing the Alpha btw). I like the way he calmly solves problem. The ML is a tsundere and spoiled by MC. He gets scared when MC try to seduce him. So if anyone know any similar novels with these characteristics, please share .
Those Years We Killed the White Lotus and Counterattack of a Villan With a Thousand Fans have a badass mc (been a while since I read them so not 100% sure). I don't think the ml was tsundere though.