OK – simpler to add the shortcode directly into the .html template, just like WooCommerce works.
Woo adds an entry directly into the
wp_posts data table for their pages. The
post_content field is a shortcode….
<!-- wp:shortcode -->[woocommerce_cart]<!-- /wp:shortcode -->
As I want to surround my block contents with my ACF extracted data I can put this markup directly into my templates.