Been enjoying using my Boox Nova Air that connects to my Kavita through Moon Reader+. I just download my epub or PDF to read. That flow has been working like a charm to me.

Keep in mind that it’s an e-reader, so it’s black and white only. May be fine with you or you may want an iPad or an Android tablet for color and speed

EDIT

Have read also from my Kindle and Kobo library as it is an Android device and have both apps downloaded