The anime was an unfortunately lackluster and disjointed adaptation, which, both as a retelling of the story and on its own merits, disappointed all around. The novels are far superior, and the manga is a near 1 to 1 retelling of the novels (and is very well drawn), so these are the recommended ways to experience the story.
The novels are official translations, pulled from Officially Translated Light Novels 14.0 (https://nyaa.iss.one/view/1338775) and the manga is fan translated and ripped from Dynasty Reader. New chapters release monthly.
Support the official releases:
Manga (first volume's official translation releasing August 24th): https://squareenixmangaandbooks.square-enix-games.com/en-us/product/9781646091065