I once read a novel where a boy turned into a girl and then traveled to a magical world to become a princess or something.

Actually, this man was an angel in his previous life. This was a novel about boys turning into girls. The man was originally a university student who bought a ring and then turned into a peerless beauty after sleeping. It turned out that the man was actually a female angel who had reincarnated into the modern world. After that, he returned to his original world through the ring. In this world, she was the daughter of an earl who had been in a deep sleep for a long time. Never woke up