I loved Annihilation (book and movie), but, until now, never got around to reading Authority, I think because I read a later sequel out of order and found it very boring.
But the Authority audiobook is great--the story's great, and the performance by Bronson Pinchot is great. It picks up right after the events of Annihilation and is about a failson FBI agent sent to the Southern Reach to figure out why their excursions keep ending in disaster. It reads like gothic horror, with the bureaucracy of the Southern Reach's headquarters serving as the decaying haunted mansion.
Available at Amazon, but I used the Libby app.