Previous, Next links on Single Product Page - NOT within category

Hi (Tom suggested I started a new topic for this.)

I want to insert Previous product and Next product links on Single Product Page, but I want to link to the next and previous product alphabetically for the whole product list, and NOT just within the same category

I've adapted the suggested Bloomer code, as below, and it works well for the next and previous within a category. (I've made it show the product %title rather than 'Previous' and 'Next'.)

I have tried FALSE, and removing 'product_cat', to get the whole list, but with no success. I also tried adding var_dump($previous); before echo $previous; as you have suggested. None has worked so far.

The priority is for it to deliver an alphabetical sequence (not the product upload sequence) for all products.

Any help gratefully received! Thank you.

add_action( 'woocommerce_after_single_product', 'bbloomer_prev_next_product' );
 
function bbloomer_prev_next_product(){
 
echo '<div class="prev_next_buttons">';
 
   // 'product_cat' will make sure to return next/prev from current category
        $previous = next_post_link('%link', '&larr; %title', TRUE, ' ', 'product_cat');
 		$next = previous_post_link('%link', '%title &rarr;', TRUE, ' ', 'product_cat');
 
   echo $previous;
   echo $next;
    
echo '</div>';
}