Hi
@FordGT90Concept. I got a similar problem. I got a 5.1 setup connected 3 with analog jacks. Windows 10 1903. Codec Realtek ALC 1150.
I left only the windows driver as you said. I configured my speakers to 5.1, full-range disabled. Then I activated Speaker Fill. But I still get the same bad distorted sound on the Rear and Central Speakers when I play Stereo music or anything else.
I tried every damn driver I found on this forum from Alan Finote. Nothing works for me, no Dolby, no DTS, no VIA HD enhancements.
Question is, do you get distorted sound as well or you get the same quality on rear as you get on front?
The funny story is that on my previous PC (Core 2 Duo generation, 2008), I had VIA HD chipset and the Speaker Fill worked great, it cloned the Stereo to all speakers very clearly.
I did find a solution, tho not perfect. In the Registry, I can remap the Rear and Sub/Central jacks to Front. Also, Speakers are configured to Stereo. That works great, but then I won't be able to play real 6 channels sources like games or movies. I have to unmap them back and restart everytime.
https://www.reaper-x.com/2012/02/13/how-to-remap-retasking-realtek-onboard-jacks-ports/