DELL Audio app conflict

Optiplex 9020 with windows 10 pro 21H2 with latest drivers installed, Realtek audio installed again several times since 2020.

This PC had too low microphone settings and I install the DELL Audio app that allows to set different microphone gain settings. This works fine as long as I use a headset with microphone: it always works.

Problems appeared on this PC when trying to use Sony WH-1000XM4 in 2020 using Bluetooth: it has never worked with MS teams or Skype. Headphones are not broken, they work fine with other windows PC, cellular phones.

The problem seems to be inside the windows system and the Dell audio settings, no other audio drivers are installed in this PC. When a mp3 is being played, the Bluetooth headphones work fine, loudspeaker settings in the DELL Audio app are fine "headphones WH-1000XM4 Stereo" but the loudspeaker settings for headset "WH-1000XM4 hands-Free-AG audio" appear twice, once force to zero, second one set to 100%. Forcing both WH settings to 100% works only for a short time, the DELL Audio settings are forced back again to 0% for first WH, 100% for second WH.

When skype settings verify mic and loudspeaker test, cable headset works fine but the Sony ones never work, no microphone, no mic signal when loudspeaker/mic are set to "WH-1000XM4 hands-Free-AG audio" 

Sony has tried to give support, 2 updates happened since 2020 but the WH has never worked as expected.
I have to keep DELL Audio app because the mic app has to be set to 12dB. Is there a work-around/registry_setting to force the PC mic gain settings by default to 12dB and allow me to delete the DELL Audio app?

Regards,

franc86899