Currently, Common Data Service (current environment) connector doesn't return option sets labels, only values.
Old Dynamics 365 connector provides this possibility.
Usual Common Data Service (not current environment) connector returns labels if you use outputs('actionname')['body/_optionsetname_label'].
Please add this possibility to Common Data Service (current environment) connector.
While it doesn't include the label as an data element in the dynamic content picker you can access it using, for example, item()?['accountratingcode@OData.Community.Display.V1.FormattedValue']