koreader feels like the best of them all. it just has so many options that configuring it feels like a full-time job
@hi KOReader can be overwhelming at first, but totally worth it. Put ZenOS on top of it and you'll get a nicer experience. From there you can explore the rest of options at your own pace.
@hi if you get to the point where ya run it on multiple devices I made a self-hostable sync server for it: https://codeberg.org/qbit/kogs :D