You could probably also give BookFusion a try. You will be able to read on iOS, Android and Web(Linux,Windows,OSX). All your eBooks will be synced across all devices, comments, highlights and reading progress.

More at https://www.bookfusion.com/reading/cloud-library . We also plan to release a native app later this year for desktops.

PS: I am the founder of BookFusion

use an Appimage for Calibre.