I have a htpc and stream from ex netflix HBO viaplay etc. I use the digital out on mainboard realtek alc887 to a DD, DTS reciever and it have worked flawless. Even DD+ movies gets tranformed to a 5.1 signal and trensfered with coax cable.
Now with 1909 update, there is only 2channel out from edge, firefox etc. Something has changed.
A good choise to test is with Dolbydigital site, where you can either play "the Leaf" in the browser or download the same mp4 file.
I have reinstalled realtek and I have 5.1 output from the mediaplayer in windows, VLC and any other player. But in a browser I only get 2channel audio.