As you say, Bardugo's Gregverse books are notorious for the poorly-researched Russian window-dressing (both when it comes to language and setting). I didn't even know any Slavic languages at the point of first reading them, and even then I knew that surnames are gendered in Russian (and Bardugo was seemingly picking male and female surnames for her characters at random), and my closest friend when I was a teenager grew up in Russia and had a younger brother called Grigori, who was of course known by the diminutive 'Grisha,' so Bardugo's use of 'Grisha' for her super scary super portentous superpowered army was never not hilarious to me. I can only imagine all this stuff being even more distracting for people with more background in the language and culture.

That's kind of what I meant when I said her other books had been written with the market in mind — there's a carelessness about them given she was either starting trends or jumping on board an existing trend at exactly the right moment. She's been tremendously successful doing so, but her commercial success and popularity doesn't necessarily make them good books (much as I adore the Six of Crows duology).

But The Familiar is about the experiences and history of Bardugo's own ancestors — she comes from a Sephardi Jewish background, the Ladino refranes that play a huge role in the book are proverbs she herself was familiar with through her family, and it just feels much more like a deeply personal labour of love.