In ArcMap, the word "Legend", under a quick right-click>Legend Properties>General>Symbol allowed user to format the legend "Title" text separate from the layers text. All without losing view of the map (in background for quick review using Apply!)
To change layers text was a quick selection of the "Items" tab>Select All> Apply (to see if the changes worked without closing the dialogue!)
In ArcGIS Pro, the entire legend changes with text changes under Ribbon>Legend>Format:
Please enable quick, simple, separate revision of Layer Text and Legend Text.