I think you missed the point of my post. Luz is not a fantasy fan. She's an Azura fan. Actual fantasy fans read more than one book or series. Luz has only shown interest in reading Azura. Her every decision was based on Azura. When she entered the writing contest she wrote a self insert Azura fanfic. Even her final battle with Belos was an Azura cosplay.
An actual fantasy fan grounded in the entire genre would draw their references from multiple sources. Plenty of online fantasy fora will frequently have questions along the lines of, "I've just finished (series X) and I loved it. What should I read next?" A person who just constantly rereads Harry Potter or Lord of the Rings is not a fantasy fan. They're just fans of those particular series.
As for not going to the library, if an actual fantasy fan found themselves in an actual magical realm where magic and magical creatures and races are walking around before their eyes and they saw a library filled with books on magic written by actual witches and wizards all filed under non-fiction you're suggesting they might not have an interest in reading any of those books? They're already voraciously reading fantasy books on earth so why wouldn't they continue voraciously reading those books in a fantasy world where magic is no longer a fantasy?