I don't know if anyone has pointed it out before, but Heronia acts just as if she's following a guide rather than playing the actual game. I mean, it's not just that she's expecting things to follow a certain route, she's even saying lines in game scenes that do not fit the reality, but instead are what she's supposed to say in that scene to get the best finish.
I think it's important to keep that in mind since, if she was someone actually skilled at otome games she probably would have been a clear threat to the protagonist since she would have had experience with finding the right thing to do to get the win.