On the main screen, before starting your recording, tab and find this option

Mute 'Desktop Audio' check box not checked

Then press space on it, and start recording.

I already told you how last time you asked this question.

Just go to the audio and where there is an audio selected, like microphone, stereomix, whatever you want to turn off, disable, just click on the drop down, if you can see it and then click on select, or whatever it is before you'd picked anything and that will help. I'm legally blind, but i still can read the print, even though it is difficult. :/

You'd need either a virtual audio cable or an external hardware device to root NVDA through (via the synthesiser [control+NVDA+S] dialogue). I've used similar setups during streams etc before and would be happy to clarify anything else if needed. Best of luck.