1. Are you sure that you cannot move the cursor to your secondary display?
Did you check the display position (via display settings window) if you are moving the cursor/window in the correct direction?
Maybe your second display is on the other side of your primary display?
2. If auto rotation is ON and spacedesk display is set as Desktop Duplication/Mirror, once you rotate your secondary display it will also automatically rotate your primary display.
Make sure that you rotate your iPad device in landscape orientation.
Can you maybe send us a picture or short video of your spacedesk setup showing the rotation issue?
3. You can search and access the “spacedesk Driver Console” via Windows start menu in case automatic start is disabled.