How to get Remote Audio Microphone working with Windows Server 2019 Remote Desktop Services

long story short, there were a few things that helped me but the 2 main reasons it would not work (Remote Audio Microphone was present but it did not made any sounds).

On the Terminal Server as an admin:

Local Computer Policy (although this settings should be enabled by default if set to “Not specified”):

Administrative Templates -> Windows Components -> Remote Desktop Services -> Remote Desktop Session Host -> Device and Resource Redirection:

Enable “Allow audio and video playback Redirection”
Enable “Allow audio recording redirection”

On the Terminal Server as the User:

Right Click “Sound” in the Taskbar (the Speaker Icon) -> Open Sound Settings -> Microphone Privacy Settings

Enable “Allow apps to access your microphone”

This made it work for me.