This is not an anti-Kindle rant. I have purchased (rented?) several Kindle titles myself.
However, YSK that you are only licensing access to the book from Amazon, you don’t own it like a physical book.
There have been cases where Amazon deletes a title from all devices. (Ironically, one version of “1984” was one such title).
https://www.nytimes.com/2009/07/18/technology/companies/18amazon.html
There have also been cases where a customer violated Amazon’s terms of service and lost access to all of their Kindle e-books. Amazon has all the power in this relationship. They can and do change the rules on us lowly peasants from time to time.
Here are the terms of use:
https://www.amazon.com/gp/help/customer/display.html?nodeId=201014950
Note, there are indeed ways to download your books and import them into something like Calibre (and remove the DRM from the books). If you do some web searches (and/or search YouTube) you can probably figure it out.
I know you guys conversed this far; just wanted to share with you that readarr functions like wet garbage compared to the other arr programs. Just don’t go in with high expectations with readarr, and if it ends up not working well (or at all), just know the other arrs are really top notch. Radarr works awesome and sonarr will literally keep your shows up to current for you. All that said too… there is a steep learning curve to this whole thing if you’re new to docker.