How to use HomePod as external speakers for Sony TV and Sky Q with Apple TV?

Can anyone help me?

I am trying set up my apple HomePods as external speakers for my Sony TV and Sky Q box.

All of the cables have been checked, the Apple TV is connected to the HDMI 3/ARC port and the HomePods work as speakers when watching tv via the Apple TV.

I have searched high and low for the answers but a lot of the answers tell me to go to the HDMI settings on my Sony TV (which I don’t have) The Apple TV isn’t showing on the Bravia Sync list but is showing on the input list and i get an error on my Apple TV when trying to set up the audio return channel.

In a nut shell; Apple TV uses the HomePods for sound. The tv and sky, use the tv speakers but I would like to use the HomePods for all three and I can’t work out where I am going wrong

[Re-Titled by Moderator]

Original Title: HomePods and Sky