I’m having trouble getting WP Discourse Plugin Tips and Tricks to work in terms of restricting available categories for a custom post type.
Discourse plugin settings include the custom post type in question (as well as other post types) and a global default Discourse category has been selected. This global setting works: the specified category is the default and you can select to publish to a different Discourse category on a case by case basis.
For this specific custom post type, I wish to restrict publishing to a single, different category. We’d like this custom post type to automatically publish to Discourse, even if that means we need to force publish because we are using the block editor per this topic: WP Discourse now supports the WordPress Block Editor.