Trying to record Oculus Quest gameplay with Backpack PC MSI VR One. First essential thing was HDMI-VGA converter. This thing makes Windows think display is still connected, and scrcpy does not turn off. Second essential thing is Ground Loop Noise Filter. I tried external sound card, Guitar 400kOhm sound card, sound card with line-in port without amp. Wasted 3 weeks to find out that real problem is ground loop. USB 3.1 has ground, and audio jack has ground, that makes a loop. Ground loop makes horrible noise.
Look for I play GOG! channel on YouTube