I have a company-managed project and I have customised my issue hierarchy, renaming Epics to Features and adding a new level.

I want to create a Scrum Board that shows only Level 1 issues - Concept, Improvement, Feature (was Epic).
I have already created a bunch of Concept, Improvement, Feature tickets as you can see by this filter search:

But only 2 are showing in my backlog:

This is my board filter:

It seems that I can only see the Feature Type tickets in my Features & Improvements panel:

I can however see the Feature tickets in the Active Sprint Board.

So it seems that it is just the backlog that doesn't display the Feature Issue Type.
Is this a limitation of Jira?
Can I configure my project to show Level 2 tickets in the Parent Sidebar and the Feature tickets in the backlog itself?