IDK. Building your own is cool in theory, but there are a bunch of options that aren't that bad price wise that run Android.
The issue is that they're made by random Chinese companies and the software support is of varying quality. A focused community effort to support an Android build explicitly for readers and to hack their way to being installable on as many as possible seems like a better plan.
I have two (13" boox max 3, 6 inch reinkstone r1 that I just grabbed because it was $140 with color) and even with the mediocre software support the reading experience is pretty decent.