Hi
Apple dropped support for 32-bit games like SimCity, beginning with MacOS Catalina 10.15. There is more information in the first post of this thread: https://answers.ea.com/t5/SimCity-2013/Mac-SimCity-and-MacOS-Catalina/m-p/8298578#M127940 , including some options for running 32-bit games after upgrading to Catalina.