I recommend the novel " The Demon Emperor's Favor: The Genius Little Poison Concubine " to you. The main character is a cold and ruthless woman who cultivates the demonic arts. She is a peerless killer in the 21st century. After she dies, her soul reincarnates into another world. In another world, she rose from the darkness and became a Godly King. This novel isn't a time-travel novel, and there's no modern female protagonist. It completely meets your requirements. I hope you like my recommendation.