I have come across a scenario recently where an organization wants their admins to control the listing of custom templates to be shown to the analytics users and want it to be separated from the Create/Curate Project permission.
As per the design currently, if a non-admin user is given permission to Create/Curate projects they can save their projects as templates and these templates then start appearing under custom templates for every other user (admin+non-admins).
In a context where organization wants only specific templates, which are created/approved by a group of admins based on business requirement, to appear under custom templates section it is not possible to do so and there is a complete mess under the custom template section.
I sugeest to consider below points in context of custom templates:
When a non-admin user with permission to create/curate projects saves the project as templates it should be visible to that user only under custom templates. There should be sharing option also to share this template with other no-admin users if required.
To make this custom template visible to all users, there should be a workflow i.e. it should be approved by an admin.