If you'd prefer to use UserVoice, here's the link. You can, however, send your feedback or suggestions by using the feedback tool (Smiley Face) in the upper-right corner of your app to send feedback directly to Microsoft team. If you want to make it bigger, you will have to change the resolution of your display of your MAC.
There is no settings in Office for MAC to make the ribbon bigger - it is not possible even in Windows.
This is Joyce, an Independent Advisor and a Microsoft user like you.
