Hi Jimbo,
managed to find a copy of the UGreen adaptor.
https://www.aliexpress.com/item/1005001734621395.html
It works !! (On my LG V40 ThinQ but not on my other, even older phone).
I can plug my phone to the Khadas Tone Board, which in turn is plugged to a JDS Atom and a HE4XX. Works...