What do you mean by subcategories?
I have hubs for major aspects of life (like you, Health, Finance, etc.) For example:
The Health hub has headings and links to notes (subcategories?) that record my history of specific health issues, dates, outcomes, medications, doctors names and phone numbers - very useful when you get to my age and doctors ask for your health history. Examples of health subcategories that get their own Notes: Dental, Heart, Hernia Repair, Prostate, Rheumatoid Arthritis, Vision.…. I was alarmed at how long this list got!
I use tags for health information that doesn't apply to a specific health issue. Websites, books, and articles on general subjects such as nutrition, vitamins, psychology, studies. I assign tags with a view to future retrieval.