Unshakable Female Lead in Regret Genre

I've awakened as the heroine in a tale of regret, and my past tormentors – the male lead and his cruel family – are busy digging their own graves. "Wow, they really put me through it... that's rough." But fear not! My decade spent enduring the worst of customer service has forged an unbreakable spirit. I can handle any scoundrel with ruthless efficiency. When faced with their venomous words, I simply retort, "Oh, really? Fine." My plan? Sever ties with my abusive family and become stronger than any man. Then, the shadowy Duke Callinos appears, proposing a marriage of convenience. "My price is five billion gold annually." He offers his name, and I accept, with one condition: "Behave in the most despicable way possible, so my family despises this marriage." Causing trouble? That's my specialty.