So, I've been a user of Litchi since my Phantom 4 Pro. Used the waypoint flying a lot back then. Stopped flying for about 3 years and times had changed. New DJI consumer drones weren't able to fly waypoints except by "virtual sticks" which was...
I'd check the settings on the RC Pro to make sure you're using an SD card in the controller and that it's been set up as the location for data, not the internal storage location.