"Mute microphone" native button doesn't work - MSI Modern 15 A10M-214XFR
Solution 1:
It seems this laptop uses some custom WMI events to implement this feature. Unfortunately the Linux driver for this does not seem to support this key. There is unfortunately no way to fix this as an end user, someone needs to add support to this to the Linux kernel.
For anyone interested in adding driver support themselves: The relevant Linux source file is https://github.com/torvalds/linux/blob/master/drivers/platform/x86/msi-wmi.c. The C# program driving this feature on Windows is located at C:\Program Files (x86)\MSI\MSI NBFoundation Service\OmApSvcBroker.exe.