Intel(R) HD Graphics 4400
Driver date: 04.11.2020
Driver version: 22.214.171.12471
I tried to update driver using autoupdate tool. It “upgraded” driver to:
Driver date: 27.12.2018
Driver version: 126.96.36.19970
Clearly - OLDER version. And voila! AudioRelay is working!
So, basicly, my problem solved, but strange way. De facto downgrading graphics (!) driver is a solution.
BTW - AR is great! Ability to play sound on output device different than default one is a killer feature for me. I have game sounds in my BT headphones, my wife got YouTube music on 5.1 logitech connected to my desktop ;D