On my Switch 7 laptop Microsoft tried installing a Windows 10 update that failed. Since then every time I restart, in Sound settings under Choose your output device, it shows No output devices found. Updating drivers and everything else I tried did not solve the problem. However here is a solution that works, sort of. I say sort of, because next time you restart you will have to do this over again.
Go to start menu.
Click on the Settings icon (it looks like a gear).
Scroll down and click on Ease of Access.
Click on Audio.
Then tap the keyboard key that increases your sound level i.e. volume.
If you now go to Sound settings you will miraculously find that you have your audio devices back.
Thread was edited to add model name to the title