Airplay 2, Libertone Zipp, YouTube and Apple TV 4k

Can't seem to get this to work as I want it. I would like to stream a YouTube video to my Apple TV 4k via stream from my IPhone using Airplay 2 and also use Airplay 2 to output audio to a couple of Libertone Zipp external speakers. It works fine except the video stops showing on the Apple TV 4k and it only outputs audio.

Is this not possible atm?