Pick a ready-made set of categories, see exactly what's in it, and import it into XPENC. A template is structure only: names, icons and colours. It carries no amounts and no personal data.
Subcategories roll their spending up into the category above them.
Needs XPENC 1.6.6 or newer (now in beta). Nothing changes in the app until you switch to the template.
.json file.Your history stays put. When you switch, categories with the same name (Rent, Food, Groceries and so on) move into place along with their transactions. Past transactions always keep the category they already have.