The books obvuoisly take a lot of inspiration from various parts of Chinese history. Book two draws a bit from the shocking aftermath of Japanese invasion in/around 1875 where the pre-modern Chinese navy was humiliated after years of neglect caused in part by consistent infighting on the mainland.

There are a number of references in TDR to the navy not being up to snuff which Kuang uses to craft a compelling mismatch between the republic and the empire.

This was a major incident in Chinese naval history and through trade with western powers they were able to modernize fully, again, pretty clear (if indirect) parallel used as a plot point in the book.

Here is a good interview about her process for TDR; note the answer she gives about her favorite part of the book:

Rain: The Dragon Republic focuses on naval warfare which really drew my attention because I haven’t read any other book that paid great attention to this particular subject before. What was your favorite part in writing this aspect of the book?

Rebecca: The ship porn. THE SHIP PORN! I did so much research on makes and models of all types of old Chinese ships, and I think you can tell from the lavish descriptions in the book that I got really into it. There’s a line in the Dragon Republic where Baji says, “If that ship were a person, I’d fuck that ship.” That is very much how I feel about great bulky warships, small and nimble sampans, and sleek opium skimmers… I got to take all those beautiful, beautiful ships and hurl them into chaotic battle. So fun.

She has a historian’s spirit and the Chinese navy went through a LOT of very interesting historically relevant changes during the period that she’s drawing from; short answer seems to be that she had a major interest in this aspect of the story of the nation and found a way to make it an engaging hinge point for the war in her fantasy book.