The Append (Data Management) geoprocessing tool is unresponsive when the Field Matching Type parameter is set to 'Use the field map to reconcile field differences' in ArcGIS Pro.
This behavior is no longer reproducible with the redesign of the field map UI beginning in ArcGIS Pro 3.2. For more information about the redesigned UI, refer to https://www.esri.com/arcgis-blog/products/arcgis-pro/analytics/big-improvements-to-the-field-map-in-arcgis/
解决办法
Export the layer created from the selection and create a new feature class in the geodatabase.
Right-click the selection layer, click Data, and click Export Features.