Books like the collapsing empire

The Collapsing Empire is a space opera novel by American writer John Scalzi. The book was published by Tor Books on March 21, 2017. It is the first of a series that was originally intended to be two books but is now a trilogy. The second book, The Consuming Fire, was released October 16, 2018 and the final book, The Last Emperox, was released on April 14, 2020.

The Interdependency is a thousand-year-old human empire of 48 star systems connected by the Flow, a network of "streams" allowing faster-than-light travel. Each stream is one way and has an entry point and an exit point. There is no faster-than-light communication faster than the Flow, and interstellar trips are not instantaneous—ships carrying mail or passengers from Hub, the capital of the empire and the system with the most Flow connections, arrive at End, the most distant, nine months later—but the network permits life-sustaining intersystem trade. As a natural phenomenon, the Flow is poorly understood; Earth disconnected from the network thousands of years ago, and civilization on another system collapsed more recently when its pathway suddenly closed.