[rambling]
I enjoyed reading the book, I just feel like it wasn't as well-connected as it could've been? I feel it could've been more united in its themes. For example, in it,

the world is set to end due to climate change,

but I feel like it wasn't touched on as much as it could've been? Like environmentalism?
Magical Girls, btw, is a genre typically focuses on young girls who get magical powers and balance their heroic responsibilities with their social/school lives. (Though admittedly, not all of them are magical/supernatural. Sometimes, the protagonist is just a very witty girl with a secret identity)
The novel subverts those tropes by having its magical girls all be adult women, though they do have costume changes. (Magical boys exist but are very rare). Within the novel,

abilities can be awakened by traumatic events.

  It uses this to explain why so many women are magical girls.

They are marginalized within their own countries and communities.

In fact,

the main antagonist is a survivor of domestic abuse who lost faith in the world.

I enjoyed how it used supernatural elements in that way, to comment on real life stuff 
I'd actually say it sort of ties into climate change disasters in that way, as in there's a terrible problem in the world that everyone knows is present. Yet, there's not enough people working/speaking against it, or the people in power aren't doing anything meaningful to change it.
The protagonist is a woman who almost committed suicide but was stopped by a magical girl (This is in the first chapter and blurb-- it's not spoilers) So, 

  she just kind of follows her around for a decent section of the book. I understand why the protagonist, as a person, would be aimless and follow her around

  But it felt like the protagonist was just being moved around by the author rather than influencing the story 
I thought the author could've made the protagonist a more active participant in the story. The story is told in 1st person and as much as I like the character's introspection, I would've like to see her act more in combination with that
The protagonist's power took me a second to understand it, I had to read the translator's thoughts about it to get it but when I did, I was like Oh. I See. (very interested)
It's a shame that it's probably a stand-alone novel because I really enjoyed the world building for it, and learning about the magical girl workforce. I enjoyed the afterwards by the cover illustrator and the translator, I found their words very endearing. It also goes without saying that the cover and inner illustrations were stylish and suited the novel well. I'm interested in whatever work the writer puts out in the future.
Nitpick: the translator uses commas and parentheses inconsistently, they'll have it like “(.)” or “().”  Like, just choose one.