Audio Host not working, high CPU usage, Windows 11

Just updated to a Windows 11 machine with Intel 2.8 GHz processor with 16 GB of RAM. Using Audacity 3.1.2. The audio host options, MME and Windows Direct Sound do not work (unresponsive to record or play buttons). WASAPI works, however, it will only recognize my mixer (Audio 2000s AMX7323) as a USB 2.0 microphone and record only in mono (stereo recording option not available). As soon as I open Audacity and make setting changes to audio host options, CPU usage pegs out at 100% and stays there, slowing response to a crawl. After closing Audacity, usage stays at 100%. Restart takes several minutes.

I’ve done everything I can think of in the way of updating drivers in Windows. Deleted and reloaded the mixer. I’m afraid there are several issues. I don’t know that this is an Audacity problem, but it leaves Audacity unusable.

Any ideas?

I’ve made some progress. Removed all RealTek audio drivers and updated drivers. With new drivers in place, the high CPU usage issue is apparently resolved. However, the audio hosts, MME and Windows Direct Sound playback at ~10% of normal speed. WASAPI plays back at normal speed but does not support stereo recording with my mixer, only mono. MME and Direct Sound appear to recognize stereo recording capability of mixer, but no way to test as they will not playback or record.

Are there any other audio hosts available for Windows, or someway to reload the current ones?