The best way to present Knowledge articles to different audiences is to use page layouts or permissions to display only the fields needed for each audience. This way, the same article can be reused for both internal and external users, but with different levels of detail and visibility. Page layouts can control which fields are shown on the article detail page, and permissions can control which fields are searchable and editable. This is more efficient and consistent than writing separate articles for each audience, which would require more maintenance and duplication. Topics and data categories are different ways of organizing articles, but they do not affect the fields that are displayed. Topics are used for external sites, such as communities or portals, and data categories are used for internal sites, such as the Salesforce app. They can be mapped to each other, but they do not have to be organized the same way. References:

5 Best Practices for Salesforce Knowledge

The Ultimate Guide to Salesforce Knowledge

How to Write a Good Knowledge Base Article

Prepare Your Salesforce Knowledge Base