Hi Aliaa Ossama and Xander Bakker,
That's correct that Arcade expressions/attribute rules cannot be used to model network connectivity between assets in the desktop editing environment.
Many water utilities that have migrated to ArcGIS Pro, still use ArcMap to make edits to the geometric network, as they plan to migrate to complete web-based utility network management. As Xander mentioned, there are many important benefits and water industry specific solutions that can be leveraged in ArcGIS Enterprise.
Have any planning activities been done with this client in regards to utility network management?