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.