You may want to investigate which features are currently in use when deleting an Edge cluster.
This KB describes how to identify objects associated with an Edge cluster.
VMware NSX
Ensure that no objects are associated with it to delete an Edge cluster.
By following the steps below to identify the Edge cluster's UUID and searching for it in the NSX Manager UI, you can determine the objects associated with the Edge cluster.
1. Log in to the NSX Manager UI.
2. Navigate to System > Fabric > Nodes > Edge Clusters.
3. Note the UUID of the target Edge Cluster.
4. Enter the UUID noted in step 3 into the global search bar at the top of the homepage and press Enter.
5. Check the search results to see if any objects are associated with the Edge Cluster.
For information on searching for objects, please refer to the following documentation.
Search for Objects