You can also use an extension method on the MapView class: AddOverlay to add a Symbol (point, line, polygon) to a MapView's grphic overlay. AddOverlay Method (MappingExtensions)—ArcGIS Pro
Here is the documentation on Graphic Overlays for MapView:
ProConcepts Map Exploration · Esri/arcgis-pro-sdk Wiki (github.com)
private IDisposable _graphic = null; //defined elsewhere
// Add point graphic to the overlay at the center of the mapView
// Note: Run within QueuedTask.Run
_graphic = mapView.AddOverlay(mapView.Extent.Center,
SymbolFactory.Instance.ConstructPointSymbol(
ColorFactory.Instance.RedRGB, 40.0, SimpleMarkerStyle.Star).MakeSymbolReference());
// Note: Update graphic using UpdateOverlay
// mapView.UpdateOverlay(_graphic,...);
_graphic.Dispose(); //Removes the graphic