What you want to do instead is go to View > Sidebar and turn it on. Well, actually it does - but you’re unlikely to turn it off by accident like you might do with the Sidebar.
This button will do nothing meaningful for you.
After many searches I found this dialog box of Outlook> Preferences > General which is the most common search result for trying to figure out how to get the panel of folders and accounts to show up in Outlook for Mac.
