I basically use Calibre ebook viewer for its configurability and customization. If you want a good ebook reader, give Foliate (https://github.com/johnfactotum/f

I basically use Calibre ebook viewer for its configurability and customization. If you want a good ebook reader, give Foliate (https://github.com/johnfactotum/foliate https://github.com/johnfactotum/foliate) a try. That and Bookworm (https://github.com/babluboy/bookworm https://github.com/babluboy/bookworm) are the best standalone ebook readers I've seen in Linux.