Stereo Mix not working, any workarounds?

Hello, I am trying to get stereo mix working. I have installed a Sound Blaster Audigy 5/Rx capable of it, but even when enabled and set to default, it does not pick up any audio. My suspected reasons are that my Blue Yeti microphone, SteelSeries Siberia Elite Prism headset (with external sound card), and possibly Virtual Audio Cable (VAC) are likely interfering with it. Here is a screenshot of my recording devices:

I have only gotten it to pick up sound with Virtual Audio Cable uninstalled and my headset + sound card disconnected, but it is impractical for me to set it up like this. I have also tried disabling other recording devices (to no avail) and reinstalling the Sound Blaster card completely. Are there any practical ways to get stereo mix to work with the headset and VAC? Or is this simply not possible without neutering my set up?

Thank you! :)

ezander11

Thank you for the response Roderunner!,

I have tried installing Realtek HD Audio drivers, but I've never successfully had Stereo Mix as an option. This is true with disabled and disconnected devices shown.