I have a Yamaha ATS-2090 which is wifi/Ethernet connected, and can be controlled by their SoundBar app (including absolute volume level setting, which is what I’m really looking to accomplish) over IP.
Roomie doesn’t discover it and attempting to manually addit fails.
Not listed as supported so no real reason why it would work. However, if I were Yamaha, I would re-use one of their many protocols we support. So almost certainly, by experimentation, one of the existing protocols would work against such a device. Otherwise, we support custom devices so you can enter the codes for it directly.