Best streaming device I ever purchased. Don’t care that it only does stereo audio, it’s plugged into my TV and then the optical out on TV is going to soundbar. I read on a review that the audio it’s using for 5.1 and 7.1 doesn’t work with optical. So an HDMI audio extractor wouldn’t fix it, it would be doing the same thing as the TV. You’d need HDMI on your soundbar or receiver.
I like my yamaha soundbar. I don’t know if yamaha has one with HDMI inputs. The Yamaha YSP-2500 Sound Bar with Bluetooth and Wireless Subwoofer has HDMI inputs, it’ll cost you a grand though.