There were a few novels that met this requirement. For example," Rise of Comics ". The protagonist traveled to a parallel world without a 2D culture. He wanted to change the fate of the anime authors and let them regain their dreams. There was also " I'm Selling Elves in the Comic World." The main character traveled to a modern world where the anime characters lived in harmony. He lived with the anime characters and started an adventure. In addition," Transformed Manga " was also a novel in which the protagonist could transform into a 2D character. I hope these recommendations can meet your needs.