Use DIVI Page-Builder templates Globally - ALWAYS. With this, all post types use the same pool of section templates

divi__all_templates_on_all_post_types.php

<?php
/**
 * Adds a divi builder to given custom post types and globalize all section templates
 *
 * @return array All post-type-names
 * @uses get_post_types()
 */
function divi_overrule_post_types() {
	return get_post_types();
}
add_filter( 'et_builder_post_types', 'divi_overrule_post_types', 100 );
add_filter( 'et_pb_show_all_layouts_built_for_post_type', 'divi_overrule_post_types', 100);