Open e-book reader? Sure, that's a really really great thing, that we (the society) need.
The problem with this is, that an ebook needs to perform a minimal set of software functions (basically parsing a book saved in some standard format, displaying it on screen, and navigating pages), and this is not hard to do... but the hard part is hardware itself... it needs to have a large, high(-ish) resolution screen, it has to be light, preferably waterproof, have some kind of back/front light, some cases available for it, very long-lasting battery, etc. Readers like the new kindles have perfected this, while still keeping users closed to amazons store, and having them do workarounds for imorting new books (calibre,...).
Instead of focusing on bare pcbs with micro switches, i'd rather focus on user-friendly hardware. You can already get friendlier kits for cheap [0].
Otherwise a great product idea
[0] https://shop.m5stack.com/products/m5paper-esp32-development-...
I don’t think it’s a hardware problem at all. Spend two years solving all those issues you just listed (or better yet just pay a talented industrial design graduate to do it for you), then tell me how to get a DRM’ed copy of any of this week’s top ten NYT bestsellers on the silly thing.