I agree - we do need to make is easier to understand and in fact we are working on an awesome new "helper" tool for Studio which will provide AI-guided assistance as you are using working on configuration.

One more thing to note - both Category and Categories are module-specific. Posts will have own data sets in Category and in Categories. Videos will have their own, etc. If you are looking for a way to have global multi-module taxonomy you would need to use Labels. Labels are linked to "Channels" which can aggregate content from multiple modules. For example if you create Labels like "Nutrition" and "Wellbeing" - you can create Posts, Videos, Albums - label them as "Nutrition" and then all those content items will show in "Nutrition" channel.