https://github.com/Kareadita/Kavita maybe?

Dawg!

Nice :-)

OT: I can see your message in my inbox and was able to teils from there, but I can’t see it in the comment section of my initial post.

I’m sorry to hear that. Why people can’t just be nice to each other, I don’t understand. Life is tough enough.

Meshtastic is one. It requires nodes you connect your self to with Bluetooth. Your mobile is the UI then. Nodes use 868Mhz and connect to each other in ranges between 10-20km. Building an own node costs about 70-90€. Check out https://meshmap.net/ to find one nearby.

Freifunk is another, which uses wifi only. It has entry/exit points to the internet on every node (but not required), using VPN tunnels to obscure the clients identity. Nodes can be linked to another in order to create a mesh network. I don’t know how popular this technology is outside Germany. https://freifunk.net/