The shape of that bottle is creepier than the text.

I know you said “self hosted”, but if you are interested in an Android app, Google Play Books does most of what you want, I think. You can upload your books, and read them on any device (with offline capabilities). But this is the Self Hosted community, so I will show myself out.

I don’t follow it very closely, but as far as I know, they are the only one implementing the open protocol they designed (which doesn’t interoperate with ActivityPub). However, there seems to be some efforts for creating a bridge: https://www.docs.bsky.app/blog/feature-bridgyfed

As you said, there are some recognizable faces and that may impact the adoption. But not being compatible with ActivityPub is a real bummer.

I think I will quit at this point.