I've been dreaming of running "full" Linux (NixOS in particular) on a phone for a while now, but it always seemed like hardware support wasn't quite there, battery life wasn't great, or the platform was too old for actual use. The Fairphone 5 has a modern SoC and has already been supported by PostmarketOS for quite some time, so running NixOS didn't seem like a huge stretch.
Granted, working speakers and microphone are essential for a phone, but it looks like they might be supported soon on this device, which would make it one of the devices with the most complete hardware support on Linux.
Still experimental for now, but already pretty usable.