PowerPoint 365 for Mac allows you to customize the Ribbon in a number of ways. You can add new Ribbon tabs, add Groups within the Ribbon tabs, and populate these Groups with useful 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 365 for Mac.