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.
The only tablet that immediately comes to mind is the Pinetab. For just reading books and satisfying your ethical requirements and running Linux, I imagine it would do the trick.
PineNote could be a good option too
+1 for Pinetab. I got a Pinetab 2 this year and I love it.
I went on Pine64.org and their hardware is a bit pricy for me.
What I want to do is buy Amazon’s HD Fire 8 for $60 and use this guide to install LineageOS on it: https://frontpagelinux.com/tutorials/how-to-install-lineage-os-on-amazon-fire-hd-8-tablet/
Are you aware that LineageOS is not Linux? It’s AOSP, which is just the open source “core” of Android. You won’t be able to install GUI Linux programs on it
Lineage is just android