You can download the files on:
Thingiverse: https://www.thingiverse.com/thing:6615905
Printables: https://www.printables.com/model/874747
FreeCAD Design Files: https://github.com/the16bitgamer/16BitVirtualStudiosDesigns/tree/main/GLoA E-Reader Cases/6 inch
The files are for all the 3D Printable components which makes up the e-reader case. What’s not included in the files is the cutting profiles for the case that holds it. But you can just use duck tape or some flexible adhesive and it’ll work. Along with the screws, nuts and magnets required.
I ended up using Koreader on a Kobo as it lets you browse via folders.
I can copy the books onto it in my preferred folder structure and just browse them as required.