There a chinese novel that begun already translated (i think) but i don't know if it dropped, ongoing, hiatus or completed. But the story at the beginning the MC is a powerful cultivator that betrayed by her close friend or adopted sister or step sister because she like the MC brother like figure (even trough he like her) and say that after her dead the MC body will be make into food and give it to the brother like figure (is a prince of another strong country) with a reason the food is a final food MC make before dead of sickness or something (actually dead because poison but no one know except the betrayer) after hearing that the MC dead and rebirth to the body of another female that just dead because the original owner fight with another female who use whip as a weapon within the same world but different time and different area or continent after sometime MC meet with the brother like figure (he somehow know to a certain point that MC will be rebirth in this area) but of course he doesn't know MC. He protective to MC female antagonist because he thought she is a rebirth of his beloved (MC) but actually not she just pretending. And the ML is a powerful cultivator from another area or continent that has connection with the royal family (the royal family even the king must follow his command) and make a sect? called demon hall or something where the MC rebirth to. BTW the MC has engagement with the prince of the royal family but it actually engagement (the betrothal gift of the from MC family is phoenix pendant or something. Note this part i don't exactly remember) to the wrong person it should be with the ML not the other prince.
Parts of what u said sounded familiar so I thought I would just give it a go and say maybe it's Ballad of Ten Thousand Gu?