EVERYONE Has Read This but Me - The Catch-Up Book Club discussion

It’s a story about one of the emperors that had taken tons of unwilling wives and this girls sister got taken and she went to BATTLE for her.
At least I believe so. I saw it in passing. Took a screenshot. Wanted to read. And then the screenshot got absolutely lost in my phone e of screenshots of book recommendations. Please please please tell me someone knows what I’m talking about.

I'm almost positive I just read that summary here on Goodreads recently, but I can't remember how I came across it! It's driving me nuts!
If you post on the Goodreads group, "What's the name of that book???" they're really good at helping find books. They've helped me find a book four times.