using product title as keywords – Automation

Hello,
I use following code in Functions.php or rank-math.php but it doesn’t work, no keyword will be added after product update :

function update_focus_keywords() {
$posts = get_posts(array(
‘posts_per_page’ => -1,
‘post_type’ => ‘product’ // Replace post with the name of your post type
));
foreach($posts as $p){
// Checks if Rank Math keyword already exists and only updates if it doesn’t have it
$rank_math_keyword = get_post_meta( $p->ID, ‘rank_math_focus_keyword’, true );
if ( ! $rank_math_keyword ){
update_post_meta($p->ID,’rank_math_focus_keyword’,strtolower(get_the_title($p->ID)));
}
}
}
add_action( ‘init’, ‘update_focus_keywords’ );

Any idea ?
Kind regards