The Blocky Theme is a classic theme that has a number of advanced features available even in the free version. For example, you can customize options for single and archive page layouts in the theme Customizer. However, for working with dynamic data and creating full custom templates you will want to use the Pro version.
The pro version of Blocksy allows you to create custom headers, footers, and theme templates. It also includes support for custom code snippets and dynamic data display of post meta. Theme Blocks are Gutenberg features for functionality such as basic front-end filters, dynamic content blocks for displaying custom fields, advanced search, post listings, and more.
While Blocksy includes its own template creation features that uses Gutenberg blocks, it is a general purpose Classic theme that also includes support for page builders, so that you can use templates created with page builders together with Blocksy.