And the winner of the inaugural Baseline Speculative Fiction Award is Arkady Martine's A Memory Called Empire. Winners of the Baselines are plucked at random from the chaos of the universe. You can still feel good about them, the same way you can feel about anything serendipitous (a leaf falling on your head, etc.).
Rather hilariously, this turned out to be the same book that won the Hugo (probably the most major award in speculative fiction). So far, the universe concurs with fandom!
First runner-up: Emma Newman, Atlas Alone
Second runner-up: Even more hilariously, this was originally Arkady Martine, A Memory Called Empire (the list is sixty books long, fwiw). However, after much internal dispute, it was determined that a book could not be runner-up to itself. The random oracle was thus consulted once more, and the second runner-up confirmed as Karen Thompson Walker's The Dreamers.