Jailbreaks will be overridden on modern Kindle firmwares unless you install an additional extension to prevent updates.

I use the "renameotabin" extension and enable Wi-Fi from time to time to load books from FTP via Koreader. It has been 3 years since I jailbroke it, and there have been no resets for me.

See https://kindlemodding.org/jailbreaking/post-jailbreak/disabl...