I would slightly uprank templates with TemplateData and downrank subpages slightly more than that uprank. That way you prioritize well documented templates and subtemplates and subpages dropdown in priority even more than undocumented templates.
reported on https://meta.wikimedia.org/wiki/Talk:WMDE_Technical_Wishes/Finding_and_inserting_templates#subpages_of_templates

Previous tasks:

• T274906: Prioritize TemplateData description when indexing/searching
• T274908: How to exclude or lower the priority of subpages in search results?