This book might be suitable for you. It's a light novel written by the author, Zebra from the South. The protagonist is also a girl who draws comics. In addition, you can also try "Chief Editor, I Want to Draw Manga". This novel was written by the author, Xue Yingfeng. It was about a chief editor who helped a girl who had no talent but had a firm belief to become a mangaka. I hope you like this fairy's recommendation. Muah ~😗
To be honest, I don't have the exact count of how many Nana manga there are. It's best to refer to official manga sources or dedicated manga communities where you can get a clear and up-to-date number.