I managed to attempt the plugin deletion/database cleanup first – I have been able to get the duplicate slugs error to go away.
I still have blank screen/entry issues with my current Divi theme/settings, but switching to twenty-nineteen theme everything appears to be working correctly.
So I’m going to attempt a fresh Divi theme install
BTW, the Geodir “Remove Data on Uninstall” option when removing the plugin did not work in my case, all geodir listings, categories and settings were retained when I deleted the plugin.