[nullify88]

I commonly Signal call my partner when we are at opposite ends of the house. I can see something like this being useful to prevent using some remote Internet server to facilitate a very local call.

I wonder if there's a home lab / self hosted solution for this.

[subscribed]

Bluetooth to reach and reliably hold a high throughout connection to the device across the house?

I don't think so.

[sardine5]

You can do a surprising amount with a low throughput connection though. I've been playing with Google's Lyra V2 codec - it chews up a fair bit of CPU, but 3.2kbps over a CodedPhy link sounds fine.