Data Category Groups are the recommended method to meet the requirement of allowing users to find relevant articles based on their location and product. Data Category Groups are collections of data categories that are used to classify articles or other types of content based on topics or criteria that make sense for your business.
Data Category Groups can be used to control the visibility and searchability of articles for different users and communities. For example, you can create a Data Category Group for Location and another one for Product, and assign data categories for each location and product that you support. You can then assign data category visibility to users or communities based on their location and product preferences, so that they only see the articles that are relevant to them. Verified References: Service Cloud Consultant Certification Guide & Tips, Data Categories Overview