The WordPress Gutenberg project’s plan for internationalization (i18n) and localization (l10n) of Full Site Editing themes (FSE) has not yet been formulated. I’ve written a proposal, entitled Internationalization and localization: translating templates and template parts, raised as Feature request #27402.
I believe that very little needs to be done to Internationalize a file containing Gutenberg blocks and HTML, and that it can be translated and localized into a statically delivered file in the user’s required locale ( language and country ) using the process described in the feature request.
This post briefly discusses some of the challenges of translating rich text content.