You left out details but I would only expect 5.1 sound from OTA (over the air) channels, streaming (Netflix, etc.) and maybe, maybe content from USB media.
Remember the right setup? All sources go to the receiver with an optical link for OTA, streaming.
I have a samsung 7100 series uhdtv that I want to connect to my 15 year old pioneer elite a/v receiver via digital optical cable. I’ve tried everything I know to do.
I cannot get the sound to come through my surround sound.