This story was a fair bit darker than I expected, so I have some mixed emotions about it.
The writing is high-quality, and I was very interested in the exploration of toxic fandom, idol worship, and creative struggles. This lent a different angle and depth to the story that I wasn't expecting. In particular I related a lot to Hijiri's impostor syndrome and distaste for her past work, and her inability to accept praise for it. Was this drawn from your own experiences at all? It rang very true for me.
On the other hand, I had a tough time rooting for the main couple. Maybe this was intentional? Hijiri at her worst is quite despicable, whereas Mayo's desperate and obsessive behavior was disturbing, bordering on frightening at times. I couldn't help but see shades of Misery here.
I was glad that the two of them recognized their toxic behaviors by the end of the story and began to move past them. Mayo does point out that they both have work to do on themselves and that that doesn't make either of them undeserving of happiness, and that's a true enough lesson.