Algol Plus Ltd

//show variations in same order as they displayed inside the product 
add_filter( 'wpo_search_products_and_variations_results', function ( $result, $term ) {
  //set necessary values
  foreach ($result as &$item) {
    $item['menu_order'] = $item['product']->get_menu_order();
    $item['parent_id'] = $item['product']->get_parent_id();
  }
  
  usort( $result, function ( $a, $b ) {
    //default sorting for simple products 
    if ($a['parent_id'] == 0 AND $b['parent_id'] == 0) {
      return strcmp( $a['sort'], $b['sort'] );
    }
    
    //sort items inside one product
    if ($a['parent_id'] == $b['parent_id']) {
      return $a['menu_order'] < $b['menu_order'] ? -1 : 1;
    }
    //sort by parents 
    return $a['parent_id'] > $b['parent_id'] ? -1 : 1;
  } );

  return $result;
}, 10, 2 );