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.
I bought a used Kobo Aura in 2014 and used it until summer 2022. Then I bought a Kobo Libra 2 and my mother got the Aura and it still works flawlessly to this day. Kobos do last a long time.