This path would be created once you compile any of the plugins, I say this looking at the XCode projects "Build Product Path" setting. I don't have a setup to build the plugin but I am pretty sure once you build the plugins this path will be created.
You need to have the correct version of SDK and XCode to successfully build the plugin. Any mismatch in this can either cause the plugin to not load at all or crash, it might also lead to build errors. Since you have Illustrator 2020 installed you need to use the CC2020 SDK. See the following screenshot from "getting started guide.pdf"