I have built a structure that highest level is EPIC (it's its own project that uses portfolio EPIC as the issuetype), and then shows features linked via "Implements" link type to the EPIC and then Stories that use the IMPLEMENTS linktype to the features, so it goes EPIC->Feature->Story as the hierarchy.
I can get the linked issues just fine, but the structure will not show EPICs that do not YET have a linked FEATURE to it.
STRUCTURE:
Add issues linked by Implements: parent is implemented by children
Filter issues: project in ( IMFTR, KWFTR, ECFTR, BXFTR, KIT, "Precision eCare", "Precision eCare Architecture", "Precision eCare CM/OPS", "Precision eCare Kiosk", "CX CPAAS Dev", "XP - Bill Explainer")
Filter issues: status != Canceled AND (resolutiondate >= -90d OR resolutiondate is EMPTY)
Insert issues: Project = Epic AND component in ( "DES","CX") and status not in (Closed,Canceled)
JIRA Data Center version 9.4
Structure: Version 9.0.1