It is acknowledged that the native Mac app deletion takes the app away only, while its associated files including caches, cookies, packages, root files, etc stay on your device still. At this moment, I guess you need a professional app uninstaller that takes the app and its related files away completely. iBoysoft MagicMenu is such an optimal utility, and it lists all the related files of the app when you perform the removal task. You can check the files you don't need any longer and delete them in one go.