View > Reset Panes
There are 3 options (mapping, editing, and geoprocessing). Unfortunately you can't restore to a set workspace that you create - maybe someday!
I would just like to see things the way they are at https://guides.library.duke.edu/arcgispro/layout
But if I try to Reset, the 3 options (mapping, editing, and geoprocessing), it didn't work.
However, clicking around, I came across Dock, and by choosing to dock for the Contents and Catalog, I was able to get the map View in the middle section, Contents in the left pane, and Catalog in the right pane