It would be great to have a geoprocessing tool and/or UI element added to the Historical Moments tool to restore features that have been deleted from the Default version of a feature layer with Branched Versioning.
The solution we received from support was to use Historical Moments to access the deleted features, export them to a feature layer on a file geodatabase and then use the Append tool to add them back to default. It worked, but it did require disabling some attribute rules...which then required stopping the feature service to free schema locks...requiring scheduling the work out-of-business-hours.