If you need cloud storage, Disroot.org has 2gb free, but… For this I think something like syncthing would work well, if you even need it in multiple places.

The download page for syncthing: https://syncthing.net/downloads/

For all the alternatives out there truth is, none are really anywhere near perfect. Matrix and most of its clients while encrypted don’t offer true jump in /jump out game chat.

After complaining about it heavily for a few days, I did find one client that has that same feel, commet.chat. I haven’t done a whole lot of testing yet, but from what I’ve seen/experienced, it’s close, if not there

Personally I still prefer XMPP+Cheogram. It’s more Signal than Discord, but it’s a lightweight chat server with voice call abilities, and that’s what I needed it for

Yep, though with calibre in particular you want to kind of make sure it’s locked down real good. People sniff for the ports it uses, so open calibre-web libraries get found quickly, and then will usually have some attempts at cracking.

I had mine set up as a local-only thing (could only access from my home WiFi), but from experiences with other apps that have similar crawlers, it takes about a week for them to be found. Just make sure everyone’s passwords are decent, or just share one account if it’s people you trust.

I need to look into calibre-web more. I definitely tried it, but I remember it being awkward. Might give it another go to see