For anyone wondering how to get the same feature on your device (not only mic-camera)

• Go to developer settings (after )
• Quick settings developer tiles
• (enable) sensors off
• Open your quick settings
• (for Samsung) you will find the tile in the 1st row 1st position
• (for aosp) you may need to add the sensors tile
• now turn this tile on
• now your camera, mic, gyroscope, etc… are off and apps will think that there’s an error with the camera or some privacy policy rule being applied

⚪ Note: this does not turn off GPS, Bluetooth, wifi, or mobile networks

EDIT: forgot to mention (as comments said)

🔴 Warning: core system services can override this setting…

a phone call will have the mic working while app calls (Whatsapp…etc) will be muted