have you ever read This is how you lose the time war? I'm considering reading that one next

Just finished it and I love it. And it actually fits into the genre I mentioned above really well.

Lesbian sci-fi? Check. 2019? Check. Debut? Kinda - seems it's the first novella of one of the authors. There are two empires, even though they're not called that. It just didn't start a series, so I guess I'll drop that part and list it as one of three books that fit the rest.

Well, I didn't really have a problem with the unique part, more that there's a lot of stuff happening that feels like filler. It's been a while, but as a I remember it there's the ancilliary, the main character, on a journey, and that is interspersed with flashbacks. Those were really interesting. The rest was mostly her being put in very dangerous situations which we knew were dangerous because the book keeps telling you just how dangerous they are, but the way the character was built up it just didn't work for me as something to build tension. Just a constant, yeah, she's going it be a badass and overcome it. And she does. And it didn't feel like it pushed the story forward, but rather allowed time to pass so there could be another interesting flashback.

The ending, when things started moving and the whole deal with multiple emperors was revealed was great, but the way to get there just wasn't doing it for me.

There was a slight annoyance with the language gender thing, since my native Czech is a gendered language, so the whole thing wasn't completely unfamiliar or surprising to me, and the way the book had to go out of its way to explain that this is what's going on, since English is not gendered and the mistakes had to be pointed out. It felt a bit tortured and overstaying its welcome, but not a dealbreaker by any means.

Anyway, adding your suggestion to my Pile. Sounds like a more serious take on One Day All This Will Be Yours by Adrian Tchaikovsky, which ultimately annoyed me with its tone and unlikeable protagonist.