Apple TV 5.1 and Atmos issue!

So I had my Apple TV 4K connected to my Samsung QN95A which had a Sony 5.1 home theatre connected over eARC...Everything worked on until I got myself a Samsung Q990B soundbar which supports atmos. Now if I set ATV audio mode to "auto" then I lose proper 5.1 surround on non-atmos content. If I set ATV to DD 5.1 then I get the surround working but obviously I lose atmos.... So wth? Can't I get both if I connect ATV directly to TV??

Now, if I connect ATV directly to the soundbar then everything works as expected - but I'd like to connect it directly to the TV to get Q-Symphony working.