Post Ligeti, got in to this, the great Hamlet Gonashvili, with the Rustavi Choir (mostly).
I have a complete album, but many of the YT recordings are the same.
Fans of Werner Herzog may recognize one song, "Tsinskaro."
There is another recording of the Rustavi Choir on Nonesuch as well, that is great.
Of note, Basiani are a young Georgian choir that have inherited the mantle, and are touring internationally.
I, like a common idiot, just missed them.