In a book hole and need help

Just finished up children of time, and can’t really find what to get into next.

I like more hard sci-fi and some existential themes. Been through the three body problem series, almost all of Alastair Reynolds books. Really loved all the Hyperion books (even endymon). And the expanse series I really loved as well as Red Rising series.

If someone could suggest something in those veins or similar they enjoyed it would be greatly appreciated!