I have a Boox Nova Air C, running Android 11.
My reading apps are Libby, Hoopla, BookFunnel, Kobo Books, Cool Reader, KOReader. I mostly use Libby and Hoopla, and turn on wifi only to sync.
I installed Aard2 as an additional dictionary option. Bromite and EinkBro browsers (never use them). Box for remote storage access, and X-plore for local file management.
This device is an ebook reader, nothing more, nothing less, and gets a lot of use.
I don't use Calibre Companion, or Google Play store.