This seems like a rare case of obliviousness on Lunaria's part. She is reincarnated isekai style so relying on what she knows and not accounting for anomalies is shortsighted. Some potentials I thought of include that the fictional Japanese town is based on a real location and only the name was changed, or the alternate realities theory where that town does exist and that is where the 'heroine' is from, and finally that it is just another fan of the game and ignored the fictional town and went with Japan as a whole.
They are already hinting at the evil saintess cliche, I really hope they don't fall into the malicious/bullying coworker that was already known in their previous life as well. It's not going to be as easy for they'd like it to go since Lunaria has already established some allies. I am hoping that the revenge against the prince will include drawing him into the woods for the animals to get their own revenge.