Based on what we've seen so far in the manhwa, Anri as FL starts strong (very likable, strong-willed etc.). As the story progresses, she becomes weak and irrational similar to other typical isekai manhwas.
ML finds out FL is the reader that freed him. From that point onwards, FL gets an identity crisis, wanted to "discover herself", left ml, and lived as a man.
You may want to see for yourself the rest of what happens.
Imho it's a story that would've benefited from ending earlier.

Stayed for the art. Found spoilers saying the last two volumes and the ending were INSANELY disappointing. FL gets a whole 180-degree character downgrade.
Don't even bother reading.