This seems kind of unnecessary, compared to Opus at ~10 kbps. If you're sending IPv6+UDP in 40 ms chunks, that's 9.6 kbps just from the packet headers (25 Hz * 40+8 bytes).
When the voice payload is smaller than the packet headers, you're well into diminishing returns territory.
Opus at 8Kbps sounds better, and commodity, inexpensive hardware like the Grandstream HT802 Analog Telephone Adapter supports this codec today (along with any cheap Android phone).
Lyra as it stands today will not support anything outside of x86-64 and ARM64 without rewriting the proprietary kernel it relies on.
When the voice payload is smaller than the packet headers, you're well into diminishing returns territory.