Test with a DVD or a dedicated 5.1 audio file to see if the hardware is actually working. Speaker Fill:
How to Install Genius Sound Maker Value 5.1 Drivers on Windows 10 Test with a DVD or a dedicated 5
The 5.1 functionality was missing. Windows treated it like a basic stereo device. No rear speakers. No subwoofer. No center channel. Test with a DVD or a dedicated 5