How to control the Volume Mixer on Windows 10 using command line?

Nircmd from the same brand NirSoft is a better solution for you.

nircmd.exe muteappvolume APPNAMEHERE 2

It has a ton more commands but this is the exact one you asked for which I use myself too.

It works 90% of the time, I am still trying to figure out why it doesn't work for some apps.

edit: If you found anything else besides this please share it.