In regards to the tablet, I’m thinking about buying an Amazon Fire HD 8 though I’m open to any and all recommendations.
As for the distro, I’m fine with Ubuntu or Linux Mint (or for that matter anything that you may recommend).
For the ebook reading software, I’m leaning towards using Foliate since it supports kindle, epub, and pdf formats, not to mention that the UI is great and intuitive.
Any android device that was released since Android 10 can take a GSI image. I know a galaxy tab 8 can run the GSI from Andy Yan based on testimonials. I will eventually install it on mine. I have it on my galaxy tab 10.1 2019 and I added MicroG. I’ve been running that for over 2 years.