Allow me to make a small recommendation for the "best related work": Ada Palmer's 'Inventing the Renaissance.'
It's a fantastic work of complex history, told with the tools of science fiction and fantasy writing. But it remains a high quality academic work: the tools are used to unravel the telling of a gay and complicated topic, but you still get the vastness.
If you like ACOUP, it should be right up your alley.
I was really put off by the Terra Ignota series. I struggled through it, but her writing really didn't gel with me. I've been resisting reading "Inventing the renaissance" because of that, though it does come highly recommended.
I found it very USian [0] - obsessed with religion (and the overt assumption that emperors are a good thing was unsettling). And I also found her position that all the best of human thought lay in the past (the greek classics and the renaissance specifically in this case) deeply at odds with my worldview.
[0] I have noticed that US writers tend to feature religion prominently in their writing (e.g. Brandon Sanderson, not that this stops me from enjoying his writing, which I do). I read a new writer and make a bet whether they're USian after a couple of chapters based on their attitude to religion, and I've been mostly right.