I read an alt-history years ago with a similar premise.
The Bubonic Plague wiped out three-quarters of Europe, so they were colonised instead of colonisers.
The leading power on earth was Aztec, with a heavy Japanese influence (because the Divine Wind did not sink the Chinese invasion fleet, many Japanese fled to Central and South America, taking with them metallurgical skills that kick-started Aztec tech).
No, I don't remember title or author.
@davidtheeviloverlord Shame, cause that sounds wonderful. @GayDeceiver
@AlliFlowers
Found it.
House of Reeds, by Thomas Harlan (2004).
https://www.kirkusreviews.com/book-reviews/thomas-harlan/house-of-reeds/
@davidtheeviloverlord Found it, but realized it’s the 2nd in a series, so I got the first book…first.
@davidtheeviloverlord Oups! (I’ll let ya know how it is.)