I'm leaving this here for others that may be looking for this.
IT CAN'T BE DONE
You need an ASIC (Applicaiton-Specific Integrated Circuit) to drive the display.
IT CAN BE DONE - read the comments below!
What I need to know is where to start doing research in how to render stuff on a replacement Kindle (preferably a paperwhite) screen.
What I want to achieve: Make a rather expensive bed-side alarm clock.
What will make it unique: It'll have a nice big e-ink display screen
1: Right now I use my cellphone as an alarm clock and I think that having that next to my bed is keeping me awake at night, so I want to move my cellphone out of the bedroom completely. This means that I need another alarm clock next to my bed.
2: I sleep in total pitch-black darkness. Even a very dim LED bugs me and will keep me from falling asleep.
So the idea, is to hook up a Pi to a new replacement Kindle screen so that there's no light. But it'd be nice to be able to touch the screen and the back-light will come on for a few seconds and then go off again so that I can see the time if I want to.
The question is: Where should I start figuring out how to insert tab A (Kindle Screen) into slot B (Raspberry Pi) and then get them to start talking to each other.
I've found people that have turned a working Kindle into a WiFi Pi terminal. But I don't want to (1) buy a whole new kindle to just be a bed-side alarm clock and (2) I don't want to void warranties by rooting any devices just to do so.
Also, I've looked at the PaPiRus, but it's way too small, even the big 2.7" one. I want something chunkier.
I bought myself the 800x600 6" epaper dispaly from Waveshare. https://www.waveshare.com/wiki/6inch_e-Paper_HAT
It dislpays an 800x600px .bmp file.
I'm busy developing the code to make a really nice clock interface. Currently there are 2 modes; Analogue and Digital.
The Analogue has 2 hands and the relevant hour and minute tick marks around the 12-hour clock face.
The Digital currently supports 2 fonts, (Digital Monospace, and Roboto Thin Italic). The digital also has the date in <day, month, date, year> format ("Saturday, August 15, 2020"). Currently also working on adding the current weather and temperature, and a 24-hour and 7-day forecast using the OpenWeatherMap API.
Here's a slightly out-of-date video (showing some of the older fonts and no date info) on YouTube