Get ACF field value from Gutenberg Block

get_block_data.php

function get_block_data($post, $block_name = 'core/heading', $field_name = "" ){
  $content = "";
  if ( has_blocks( $post->post_content ) && !empty($field_name )) {
    $blocks = parse_blocks( $post->post_content );
    foreach($blocks as $block){
      if ( $block['blockName'] === $block_name ) {
        if(isset($block["attrs"]["data"][$field_name ])){
          $content = $block["attrs"]["data"][$field_name ];
        }
      }
    }
  }
  return $content;
}
global $post;
get_block_data($post, 'acf/image-text', 'title');