Seth Dickinson's "Exordia" is as if you threw Neal Stephenson, Scott Alexander, and Jeff VanderMeer in a blender, added in immensely better editing and attention to prose, and added in only a somewhat more satisfying ending. It's an excellent metaphysical science-fiction work.
Ignoring themes: the overall plot is about first contact with aliens. It starts with the New-York-City-located, genocide-survivor protagonist meeting a many-headed snake-like alien who is a rebel against the snake-alien galactic empire; the books looks like it's gearing up to be a fish-out-of-water buddy story; and then -- to the surprise of absolutely no one who has read Seth Dickinson before -- turns much, much darker. (To my delight, it left NYC after starting there, which does not feel like a common feature of the writing of NYC-centered authors.)
The thematic core is ethics, the kind of people who embrace different ethics, and the kind of situations that reward or punish different ethics. When I say "the core is ethics" this makes it sound like a really drab didactic first novel from a philosophy student -- so, I hasten to add, it is nothing like that. A central conflict in the novel is between someone whom you'd tend to call a consequentialist, and another person whom you'd tend to call a virtue ethicist -- but the conflict lives in a way I find hard to communicate. Think of how Dostoevsky's characters do emulate different types of philosophy, but don't necessarily feel like little shadow-pupppets of them. And this has a lot more realism than Dostoevsky. It asks -- what kind of person embraces consequentialism or virtue ethics? how does that influence their friendships? what kind of a job will they get?
The reason I compare it to Neal Stephenson is that Neal Stephenson loves to draw the weird-ass details in his novels from reality; writing about things that actually exist as if they were strange and surprising bits of world-building in a science-fiction novel. A big chunk of the details in this novel are similarly drawn from real-world history. Seth, in general, also grinds up these details into small bits so they feel like natural parts of the world, rather than sociology or history infodumps. (In only his third Baru Cormorant novel was there a part where I said "Haha Seth! I have you, you've read "The Secret of Our Success"".)
Unlike Neal Stephenson, and in keeping with the themes of this novel -- a pretty large chunk of the background of this novel is, in fact, the ways that America has been pretty evil in its foreign policy. This makes it at least sometimes uncomfortable to read for an American, together with the multiple in-world lasagna-layers of Trolley Problem that constitute the plot.
But -- as for Seth Dickinson's Baru Cormorant -- the truly right view never really gets given to you, which is what makes it still something that can work as literature and not as propaganda. There isn't, as far as I can tell, a perspective character who says "And that's the way it should have been." Instead, people make decisions and the consequences of their decisions happen.
I compare it to Scott Alexander's Unsong because it's hard to find such straightforwardly, cosmic metaphysics in a novel. Both deal with the nature of right and wrong; the reason the universe exists; the nature of the soul; and so on. But this has.... much, much better attention to detail and editing than does Unsong.
The obligatory "not perfect" part of the review: it has a lot of tonal shifts, and these will be hard for different people. We switch from buddy comedy, to alien horror mystery puzzle, to Warhammer 40k-esque levels of physical and metaphysical conflict. The ending resolves a lot, but leaves... a great deal unresolved, and is not particularly happy. So this book will not be everyone's favorite.
But -- in exchange for Seth Dickinson apparently giving up the attraction of mass appeal -- you do get an absolutely engaging novel, and one which I really recommend.