>>100750937Pocketbook used to have pure Linux and microSD and they did release Kaleido 1/2 e-readers with them but they dropped the microSD from newer readers and have started to adopt Android.
You don't need to use Google for Android. At most you need an alternative source for extra software if you want more than the default. Some of the Android based readers don't even support Google Play and sometimes don't even support installing your own software.
Kobo has started using Kaleido 3 and is still sticking to their own Linux derivative but there's no way to expand the storage.
The Dasung Paperlike Color technically applies since it's just a monitor you could hook up to whatever computer you want.