VCDS uses a different CANID which is translates to the right one by the gateway.
So to be able to use VCDS it will be easiest to add a gateway to your setup.
Thank you, problem was in 1K0 GW, which was too old for this dash, I have borrowed 7N0907530 from my car and diagnostics worked ok with this.
Next part of this testing bench is RPM and speed emulator, got some example code from the net but not everything works, probably some logging will be needed...