Thanks to Google Translate:
This work, in its final stages, seemed to rush through multiple themes, resulting in an abrupt and somewhat unsatisfying ending.
The author reported on their blog that the progression and ending were as planned, but I don't think so.
The art style wasn't suitable for the young male target audience of the magazine it was serialized in, and the cover art for the collected volumes was embarrassing for young men to buy, resulting in mediocre sales.