Followed the instructions here:
But the workspaces stubbornly remain in the left nav. Despite having no issues, workflows or other resources linked to the workspaces.
The following developer tools screenshot, is from the point I clicked on the “I understand, delete this workspace” in the “Edit Workspace” display.
There’s a very brief message popup - perhaps “Unable to delete workspace” - hard to tell because within a second the workspace is refreshed.