Well, I think I can call this one resolved! I only installed the driver that came with the card because I couldn't find another way to test the surround speakers in my SSF. That's where the really old .dll came from (2015). I removed the drivers and let Windows install its own (2019). This worked but I was back to not having a way to test/configure the surround speakers. I decided to check the control panel, and I saw the USB Audio device. I checked the menu and was able to find a configuration screen! I then tested with PinVol, EqAPO, Thump and its all working. More importantly, the PBX problem is gone!