Oh, great, milady133, I didn't even know about Calibre-Web before.
I found this:
https://dev.to/setevoy/calibre-web-h...n-android-1ho0 and I will have a closer look, maybe it will prove a reasonable alternative, perhaps using a good ereader app and the Nextcloud connection on mobile devices ... let's explore, as best as we can.
PeterT, I don't know enough computer technology to understand how containers would work. Also you seem to use Linux, while I'm still on Windows (I have started exploring Linux, but it's hard if you're not a computer person by training).