Hi there,
The Headline block wasn’t built with the purpose of outputting paragraphs of text.
This would be better in our Dynamic Content block, however it isn’t currently possible to output custom post meta. I’ve logged an issue for this.
For now, you’ll want to simply create a shortcode and use it in your template:
add_shortcode( 'my_meta_content', function() {
return get_post_meta( get_the_ID(), 'my_meta_key', true );
} );