Get ACF Block fields outside block template

get_acf_field.php

<?php

// *******************************
// Get ACF block fields outside block templates
// -------------------------------
function get_block_field( $field_id, $post_id = '' ) {
	
	// Get current post ID if post_id arg isn't passed
	$post_id = $post_id ? $post_id : get_the_ID();

	// Get the post object
	$post = get_post( $post_id ); 
	if ( has_blocks( $post->post_content ) ) {
		
		// Parse the post content
		$blocks = parse_blocks( $post->post_content );
	
		// Look for keys that contain the ACF field ID we're looking for
		$result = array_get_values_by_key_search( $blocks , $field_id );
		
		return $result;
	}
	return false;
}


// *******************************
// HELPER: Array key search to return values
// -------------------------------
function array_get_values_by_key_search( $array , $field_id ) {
	$result = array();
	foreach( $array as $key => $value ) {
		if( is_array( $value ) ) {
			$result = $result + array_get_values_by_key_search( $value , $field_id );
		} elseif ( strpos( $key , $field_id ) !== false ) {
			$result[ $key ] = $value;
		}
	}
	return $result;
}

This only returns strings not arrays. So it's not super flexible but works for what I needed. I wanted a "HTML Anchor" clone field on all my blocks and then grab all the anchors for a page in page.php template. The only option seems to be to scrape post_content since ACF Blocks doesn't save anything to postmeta. And using 'supports' => anchor didn't help as that only seems to work for the core/heading block. Nothing seems to get saved to the database when using the Gutenberg anchor field on other block types so I just used an ACF field.