PowerPoint 2016 for Mac allows you to customize the Ribbon in a number of ways. You can add Ribbon tabs, add Groups, and populate these with commands. And if you think you made a mess and were better off with the defaults, then you can always get back to square one by choosing to reset changes made to one tab of the Ribbon, or even all tabs.
Learn how to reset, export, and import Ribbon customizations in PowerPoint 2016 for Mac.