There are internet router&modem devices out there that offer a variety of features including smarthome and classic landline voip-calls via your internetprovider.
For example the FRITZ!(fka AVM) FRITZ!Box 5690 Pro fibre router connects via Zigbee and DECT to various sensors and actors. These can be controlled over Smartphone apps remotely or the routers webinterface
The TPlink vx800 provides Phone Call ability.
These devices offer the possibility to blacklist phone calls and monitor incoming and outgoing calls.
It would be nice if we could see see and control phone calls & smarthome data from KDE enabled devices directly.
We have Android Apps like Tellows and Phoneblock to screen incoming calls for suspicious activity and deny known bad actors, we have a Windows App for AVM/Fritz devices like SpamBlockUp. It would be great if we had a native way for a linux system to get this done in the background and have a nicely looking app if we want to list previous calls or change & view settings. KDE Connect but for routers instead of Smartphones, maybe you can call it that way.