Questions for the new reprint of the Horus Heresy saga

Hello,

I’ve never read a Black Library bookdirectly, as they’re very hard to find in French (and reading a whole book in English is still less enjoyable)

But since last year, there’s been a French reissue of the Horus Heresy saga for 16€/volume ( we're at vol 2 so far and next month 3rd ) https://www.warhammer-community.com/en-gb/articles/17oswfuf/world-championships-preview-experience-the-greatest-hits-of-the-horus-heresy-saga-in-a-new-curated-series/

Are the 12 books any good & worth? Or some need a skip?

I’ve also noticed that The Dropsite Massacre is available in french, but it isn’t listed as part of the saga, is that because it’s a more recent story? I have to see it as a "stand alone" novel?