It would be great, if at the time of selecting a feature in ArcGIS Pro, the size or the radius is shown in the interactive selection graphic.
Thanks for submitting this, Karsten. This idea might be similar to Ground Distance Template Cursor.
I also wanted to make sure that you're aware of the capability in ArcGIS Pro to Display the interactive selection graphic:
and Editing grid: Turn the editing grid on or off—ArcGIS Pro | ArcGIS Desktop
You might be able to use this functionality to get what you need:
Retrieving data ...