Wow I finally found an essay by Brian McHale that unpacks my absolute favorite thing about Pynchon's "Against the Day" -- the fact that the novel, which takes place from 1893 to ~1920, travels through literary genres, synchronized in the narrative timeline with the era they were popular in our own reality.
He also pinpoints Pynchon's queering of the British spy novel, which I love (quote attached).
I've put the essay here though will take it down in a few days: