It’s probably Blindsight by Peter Watts.
Blade of Tyshalle by Matthew Stover is a sneaky underrated choice that’s simply more smart, thoughtful, AND asskicking than just about every SF book with a larger reputation.
Two completely different examples of science fiction. Both top shelf speculative fiction.
Blindsight might be a challenging book if you’re vice is more space sword I have a destiny science fiction though I find it more enjoyable than other good hard science fiction by the likes of say a Greg Egan. Watts is able to avoid making it a joyless endeavor, as some books feel like fictionalized text books with a story wrapped around it just because. In the same sense I’ve always felt like Ken MacLeod’s Learning the World is a vastly underrated first contact novel.
Blade of Tyshalle could be construed as fantasy and continues a story in Stover’s Heroes Die. Stover’s Caine books feels a bit like a cult favorite but they should not be. They in fact feel more like the ideal as Stover is deep in all of character elements that make reading Gene Wolfe feel weighty, have you questioning who you are following like Stephen Donaldson does, yet has it offset by being perhaps the best visceral action writer writing today.
Stover didn’t make a choice, he put all of the good shit in this. I like Heroes Dies very much but I think Blade of Tyshalle is a masterpiece.