Installing custom build of muditaOS on MY OWN phone

There are a lot of open source fonts. That should be easy to solve. I saw something that the big hold up was one .bin file, that is the drive for the eink display. Is that the biggest challenge?
I’m wondering if a suitable open source drive could be3 taken from one of these projects:
Quill OS

The Open Book Project

Libros, the firmware for the open book project

Would any of those help provide missing pieces to make it possible to fully open the mudita phone and mudita os?