I had a Windows Server 2022 RDSH terminal server that was moved to a new domain and would persistently lock the screen on idle for all users including administrators and require them to log in again.
Most guides reference the below Group Policy options, but none of these applied:
Computer Configuration -> Policies -> Administrative Templates -> Windows Components -> Remote Desktop Services -> Remote Desktop Session Host -> Session Time Limits
What I found was a setting that had been applied by a GPO in the previous domain and it retained the value when the server was joined to the new domain (which did not have the same GPO).
Computer Configuration > Windows Settings > Security Settings > Local Policies > Security Options > Interactive logon: Machine inactivity limit
Setting it to zero seconds prevented the issue from reoccuring.