Many with trade offs. I recommend the pocketbook 4. You can disable recommendations easily, and the unit mounts as a disk so you can read and write books as if it were an SD card.
No internet required. No sync software required. It’s quite nice!
I really liked my PocketBook InkPad Lite. After the one-time firmware update, I put it into airplane mode permanently, and always just updated DRM-free books on by plugging it in as USB Storage, and `rsync`-ing `~/doc/` to it.
The update script was pretty much this (on a laptop set up not to automatically mount removable filesystems):
Ditto. It's also significantly lighter weight than competing readers (at least when I bought mine), has physical buttons, has color models, and has really good battery life possibly because it runs a custom Linux instead of Android.
No internet required. No sync software required. It’s quite nice!