Right click my computer and go to properties. Then the remote tab and untick ‘enabled remote desktop’.
If you want to make doubly sure also put in a block on the firewall for comms on port 3389 (default RDP port).
This will stop EVERYone from remoting to the server using RDP. Admins will still be able to use VNC clients to remotely manage servers however.
It’s a good way for your purpose