Hyejung loved to read to escape her daily stress. But that’s before she woke up inside the bizarre world of her favorite novel! Instead of the main heroine who courts three eligible men, she is now Latte Ectrie – a minor villain that everyone hates?!
The series is completed, as is its sequel series. It did well enough in Korea to justify a webtoon, which got translated into English and has done pretty well for itself. It already has a fanbase here of people who would buy the book, myself included. The author is Ellianyang or 엘리아냥.
I'm not sure how many books are in the series, just that it has been published in print format. There are about 7 books total, according to Google Books, but there may be 1-2 more.
https://www.google.com/search?tbo=p&tbm=bks&q=bibliogroup:"구경하는+들러리양"&source=gbs_metadata_r&cad=4