Happy-making books are all alike, but books that displease me sure do create content.
There are two possibilities with this book. The first is that it's doing something I don't like and I'm just not well equipped to judge whether it's doing it well or poorly. The second is that it's doing something I like badly enough that I don't like it.
I'm absolutely willing to grant that this is a Yellow Wallpaper book - another story I intensely dislike because the atmosphere makes me feel awful.

This book plays with the mind and agency in a similar fashion and is disjointed in a way that perhaps reflects the experience of the main character.

Having said that, it really didn't work for me. I question some of the narrative choices and how Fox chose to convey Ivy's experience to the reader felt not so much like breaking the fourth wall, but more like being trapped in a squishy fourth wall of goo and I just found it unpleasant.
Also the male characters in this book had...basically no personality

at least from the reader's perspective, given the storytelling choices

and at no point acted beyond stereotypical and, like, as a follow-up to Erik Hoel's comment in the previous book that thank goodness Freud discovered trauma so that creators had an extrinsic way to explain emotion, wow did this book go hard on uninteresting motives that make for uninteresting characters. Also incoherent! Ivy's choices and behavior are so fundamentally incoherent and the only excuse that I have for it is that everyone else is rolling 1s on every action.
I also just no longer find stories that present

the choice between people manipulating the main character for their profit versus the ones manipulating her for her own good

to be a decent choice anymore. Give people in books better options.