Sounds like an interesting project. Need to test it!
I wrote a basic softphone for #nostr (it uses nostr relays for #webrtc signaling) called #voistr: https://voistr.codeberg.page/
More features are planned, chat and maybe video calls. Both the signaling exchange and the voistr protocol use NIP-44 encrypted events. Follow voistr here: nostr:npub1lcfnjgme4s9whl6n4fym0ft034rdmghahal7jzg7zw35w8f6dq2s2kn6vm
Discussion
Thanks, i've only tested it locally for now but i think that with a real call there might be some latency issues with the audio encoding part. Audio encoding is opus 48khz mono by default.