demo: https://x.com/adtac_/status/1820127470613622950 (3.5 fps, Paperwhite 3)
mobileread.com is your best resource here, follow the instructions from the LanguageBreak thread
I didn't really follow the LanguageBreak instructions because I didn't care about most of the features + I was curious to do it myself, but the LanguageBreak github repo was invaluable for debugging