Are there any Doujin novels that have Xiao Mai as the main character and the male lead as the main element?

Yes, I recommend 'My Little Sister Is Little Bury'. The male lead was called Haruki, and he discovered that his sister was actually Burial, a hamster elf. The story revolved around their growth and interaction. Other than that, there were also characters from other works, such as "Little Burial of the Dry Girl" and "The Story of Youth in Love". I hope you like this fairy's recommendation. Muah ~😗