I made a modified for plugin KFX Output, as calibre not support zh-hant, I added some code to convert zh-TW to zh-hant to support kindle's Traditional Chinese.
Repo is here
https://github.com/lcandy2/calibre-k...tional-chinese (readme in Traditional Chinese)
But using calibre build-in function send-to-kindle, I don't know what calibre did with the kfx file, the kfx sent to kindle by calibre will be recognized to Simplified Chinese again. Replacing the kfx file sent by calibre with the original calibre library one by manually copying files, renaming files, replacing files could solve the problem.