Populate acf-field, depending on block name

by

You are calling get_post() using null. Try to retrieve the post individually. Use get_post(get_the_ID()) to get the post content.

$post = get_post(get_the_ID());
if ( has_blocks( $post->post_content ) ) {
    $blocks = parse_blocks( $post->post_content );
    if ( $blocks[0]['blockName'] === 'acf/full-width-talker' ) {
  
    }
}