Wondering where the RemoteApp and Desktop Connections GPO Settings are? The RemoteApp and Desktop Connections group policy settings don’t require an ADMX file and aren’t hidden, they’re just unexpectedly located in the User Policy, rather than the computer one, here:
User Configuration -> Administrative Templates -> Windows Components -> Remote Desktop Services -> RemoteApp and Desktop Connections
The GPO you’re looking for is called Specify default connection URL
For your convenience, here’s the default RemoteApp and Desktop Connections URL: https://servername/RdWeb/Pages/en-US/Default.aspx