Is there a way to replicate the functionality in Wordpress where clicking a Categories button/link determines/filters which tagged content dynamically loads into the current page. E.g. Project A can be tagged for Corporate Video and Promotional Video.
Yes, you can do this by creating collection “Tags” and then in the “Projects” collection settings add few reference fields (3 maximum), which will connect to collection “Tags”. In this way you will be able to connect every project to maximum 3 tags and then you will be able to filter Project collection by this tags.