Which novels can you recommend to help me find the name of the novel I forgot?

After the female protagonist transmigrated, she became a princess, but she was not favored. Then she went to school to learn magic. In fact, the female protagonist was a phoenix god of war in the divine realm ten thousand years ago. Ten thousand years ago, she fell in love with the demon king male protagonist. After transmigrating, she met the male protagonist. At that time, the male protagonist was a prince of a country. Then, after the male protagonist disappeared, he returned to his identity as the demon king. He forgot that he liked the female protagonist before, but he had a feeling that the male protagonist had a head of white hair and had four subordinates.