I recommend 'The End of the Crows' to you. The male protagonist is Kang Xi, and the female protagonist is Yi Fei's sister. Xie Xianyun, the female protagonist, was a lonely alien in the 21st century. She was overly addicted to books about the Qing Dynasty. When she was 16 years old, she met a Qing Dynasty prince named Yinxiang. In an unexpected situation, she traveled through time and space to the second year of Kangxi and became the personal palace maid of Xiaozhuang, Su Mo 'er, taking the opportunity to wait for the birth of Yinxiang. However, she still had to face her aging body and the foregone conclusion of history. I hope you like my recommendation.