I download the ebooks themselves using the Kindle application on my computer (if I'm using Amazon to get them, which I don't always), and then use Calibre to manage/import/convert/strip DRM from them. I don't need the sync functionality, or to be able to look things up on the internet (not being able to do that is a feature as far as I'm concerned!). I just want text on a page. I like the "e-reader" experience, and I have no desire to read books on a phone or tablet. I have one Kindle, and it comes with me if I think I'm going to have the opportunity to read when I'm out of the house.
Of course, if you're using Amazon to get your books they'll still build a profile of your reading habits, but there's something about tracking the exact parts of a book I'm reading, the bits I might linger on or reread, which feels extra intrusive to me, and which I categorically don't want.
I also never connect my Kindle to the internet. (The phone app does connect.) You don't have to allow it to connect to Amazon once. Mine has never connected.
It does mean that if you want to be absolutely sure your Kindle isn't phoning home, you can't use the Kindle browser, and you need a laptop or similar to download the things you want to transfer over. It's not a perfect solution for everyone, but for the typical HN reader who is concerned about telemetry, it should work.