The Duke's Bored Daughter is My Master summary:
Dante Renatus, who had even claimed the throne as the Emperor with her excellent swordsmanship, is reincarnated as 'Helena', the daughter of the Duke of Peresca 500 years later. A second life she hadn't wanted. She had already enjoyed everything in her previous life, and had tried everything she had wanted to try. If she has to be reborn, it's just annoying and boring no matter what she does. In the meantime, Prince Caesar visits the duke to avoid a power struggle, and Helena, who recognizes Caesar's talent, decides to become his swordsmanship teacher. "I'll make you an Emperor." It was just something I started thinking about, using the skills of my previous life to train future students and liven up my boring life. But even if you like me, don't you think you like me a bit too much?