I keep thinking of setting up something like this with Twilio as a backup... I don't trust GV to stay around forever... especially since it seems like they just stopped supporting voicemail transcription for a while (iirc over a month) and the settings and integrations seem to be left to die...

I haven't looked in a while, but running a Virtual PBX via Twilio or similar is really interesting to me... and something I'm surprised more aren't taking on, considering I've seen the amount of what providers for SIP support are charging.