Gutenberg Compatibility - Importing Posts
How to Use Gutenberg when Importing Posts
The core WP RSS Aggregator plugin and Advanced Bundle Add-ons use the built-in WordPress Post type to display feed items on the front-end of your site.
Add your feed source and adjust your settings as needed, then pull in your feed items as a post.
Viewing or editing each feed item in the backend is just the same as you would for a WordPress Post using the new Gutenberg block editor. All post content is imported into a Classic block and displayed together. It is not split into individual blocks for content, images, and so on.