Homepod not linking with apple tv

I’ve been using my HomePod as a speaker with my Apple TV for quite a while now but 2 days ago I got a new tv and since then I cannot get them to work together. I have gone from a 43” Sony tv to a 55” 4K Sony tv. Now I know that the tv is really only acting as a monitor and shouldn’t really have any impact on the HomePod playing the Apple TV sound but it’s the only thing that has changed, unless there are some settings that I need to change.

Apple TV saw that I had gone to a 4K tv and changed the video settings to 4K and the sound to Dolby Atmos, as the tv has that build in. I’ve tried to reset the HomePod several times now and the Apple TV 3-4 times, even with Apple support on the phone too. If I don’t try to use the HomePod as a speaker for the Apple TV then it works fine, I can airplay to it from my iPhone and iPad and the Apple TV sees the HomePod but as soon as I try to connect the 2 nothing will connect.

ive been trying to sort this out for 2 days now and I’m literally pulling my hair out so any help would be great, thanks in advance.