get_block_templates() gets all block_templates on the site, but I just want the ones that are loaded for the current page.
I’m trying to check if there is a shortcode inside one of the Gutenberg site-editor templates. It’s not saved in $post_content or $template.

This works to check every single one

    $templates = get_posts(array(
        'post_type' => array('wp_template'),
        'numberposts' => -1,
        'fields' => 'ids'
    ));
    
    foreach ($templates as $template_id) {
        $template_content = get_post_field('post_content', $template_id);
        if (has_shortcode($template_content, 'xxxx')) {
            styles_and_scripts();
            return;
        }
    }

But I only want to check what loads on the page.
I saw query monitor plugin does output the main block template under the tab templates > block template

This is the query monitor code that outputs the correct template and seems to get its id:

                echo '<p>';
                // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
                echo self::build_link(
                    QM_Util::get_site_editor_url( $data->block_template->id, 'wp_template' ),
                    esc_html( $data->block_template->id )
                );
                echo '</p>';
            }

I was able to reverse QAs solution to output the template content but this is not ideal:

class Template_Debugger {
    protected $template_path = '';
    protected $block_template = null;

    public function __construct() {
        add_action('template_redirect', [$this, 'action_template_redirect']);
        add_action('wp_footer', [$this, 'output_template_data']);
    }

    public function action_template_redirect() {
        add_filter('template_include', [$this, 'filter_template_include'], PHP_INT_MAX);
        $this->detect_block_template();
    }

    public function filter_template_include($template_path) {
        $this->template_path = $template_path;

        if ($this->block_template instanceof WP_Block_Template) {
            $this->template_path = $this->block_template->theme . '/' . $this->block_template->slug;
        }

        return $template_path;
    }

    public function output_template_data() {
        if ($this->template_path) {
            $contents = $this->get_template_contents();
            if ($contents) {
                echo '<pre>' . esc_html($contents) . '</pre>';
            }
        }
    }

    protected function detect_block_template() {
        foreach ($this->get_query_template_names() as $template => $conditional) {
            if ($this->block_template) {
                break;
            }
            $get_template = "get_{$template}_template";
            if (function_exists($conditional) && function_exists($get_template) && call_user_func($conditional)) {
                $filter = str_replace('_', '', $template);
                add_filter("{$filter}_template_hierarchy", [$this, 'filter_template_hierarchy'], PHP_INT_MAX);
                add_filter("{$filter}_template", [$this, 'filter_template'], PHP_INT_MAX, 3);
                call_user_func($get_template);
                remove_filter("{$filter}_template_hierarchy", [$this, 'filter_template_hierarchy'], PHP_INT_MAX);
                remove_filter("{$filter}_template", [$this, 'filter_template'], PHP_INT_MAX);
            }
        }
    }

    public function filter_template_hierarchy($templates) {
        return $templates;
    }

    public function filter_template($template, $type, $templates) {
        $block_template = $this->wp_resolve_block_template($type, $templates, $template);
        if ($block_template) {
            $this->block_template = $block_template;
            $this->template_path = $block_template->theme . '/' . $block_template->slug;
        }
        return $template;
    }

    protected function wp_resolve_block_template($template_type, $template_hierarchy, $fallback_template) {
        if (!function_exists('resolve_block_template') || !current_theme_supports('block-templates')) {
            return null;
        }
        return resolve_block_template($template_type, $template_hierarchy, $fallback_template);
    }

    protected function get_template_contents() {
        if (!$this->template_path) {
            return null;
        }

        if ($this->block_template instanceof WP_Block_Template) {
            $template = get_block_template($this->block_template->id, 'wp_template');
            return $template ? $template->content : null;
        } else {
            return file_exists($this->template_path) ? file_get_contents($this->template_path) : null;
        }
    }

    protected function get_query_template_names() {
        return [
            'embed' => 'is_embed',
            '404' => 'is_404',
            'search' => 'is_search',
            'front_page' => 'is_front_page',
            'home' => 'is_home',
            'privacy_policy' => 'is_privacy_policy',
            'post_type_archive' => 'is_post_type_archive',
            'taxonomy' => 'is_tax',
            'attachment' => 'is_attachment',
            'single' => 'is_single',
            'page' => 'is_page',
            'singular' => 'is_singular',
            'category' => 'is_category',
            'tag' => 'is_tag',
            'author' => 'is_author',
            'date' => 'is_date',
            'archive' => 'is_archive',
            'index' => '__return_true',
        ];
    }
}

new Template_Debugger();

$post_content outputs everything easily. How can I get the gutenberg site created page content in a simply way like that instead of the solution I have?

get_block_template() would work perfectly but I need a simple way to get the template id outside of my monster of a solution.