How do I disable Keyboard Setup Assistant so I can use a KVM switch without getting the popup?

Mid-2014 iMac running Catalina. Using a KVM switch to toggle keyboard and mouse between iMac and MBP. Have disabled the two obvious settings in System Preferences--> Settings --> Bluetooth --> Advanced and also turned Bluetooth off but still keep getting popup whenever I toggle over to MBP. Odd thing is when I first moved to Catalina, this didn't happen; was either a Software Update or when I had to do a complete reinstall on a new boot drive. Any help is appreciated!