Seo friendly url issue in opencart 2.x

Question

I am trying to make seo friendly urls in my oc 2.x site. For category, product page, product display page etc its working very well. but for cart, contact, checkout page it is not working.

1. I found one solution on that without disturbing core files in opencart forum. It gives me urls in click but showing error on page. (page not found)

2. I also tried other solution How can I create custom SEO-friendly URLs in OpenCart?. pastebin after changes

   <?php
   class ControllerCommonSeoUrl extends Controller {
           public function index() {
                   // Add rewrite to url class
                   if ($this->config->get('config_seo_url')) {
                           $this->url->addRewrite($this);
                   }
   
                   // Decode URL
                   if (isset($this->request->get['_route_'])) {
                           $parts = explode('/', $this->request->get['_route_']);
   
                           // remove any empty arrays from trailing
                           if (utf8_strlen(end($parts)) == 0) {
                                   array_pop($parts);
                           }
   
                           foreach ($parts as $part) {
                                   $query = $this->db->query("SELECT * FROM " . DB_PREFIX . "url_alias WHERE keyword = '" . $this->db->escape($part) . "'");
   
                                   if ($query->num_rows) {
                                           $url = explode('=', $query->row['query']);
   
                                           if ($url[0] == 'product_id') {
                                                   $this->request->get['product_id'] = $url[1];
                                           }
   
                                           if ($url[0] == 'category_id') {
                                                   if (!isset($this->request->get['path'])) {
                                                           $this->request->get['path'] = $url[1];
                                                   } else {
                                                           $this->request->get['path'] .= '_' . $url[1];
                                                   }
                                           }
   
                                           if ($url[0] == 'manufacturer_id') {
                                                   $this->request->get['manufacturer_id'] = $url[1];
                                           }
   
                                           if ($url[0] == 'information_id') {
                                                   $this->request->get['information_id'] = $url[1];
                                           }
   
                                           if ($query->row['query'] && $url[0] != 'information_id' && $url[0] != 'manufacturer_id' && $url[0] != 'category_id' && $url[0] != 'product_id') {
                                                   $this->request->get['route'] = $query->row['query'];
                                           }
                                   } else {
                                           $this->request->get['route'] = 'error/not_found';
   
                                           break;
                                   }
                           }
   
                           if (!isset($this->request->get['route'])) {
                                   if (isset($this->request->get['product_id'])) {
                                           $this->request->get['route'] = 'product/product';
                                   } elseif (isset($this->request->get['path'])) {
                                           $this->request->get['route'] = 'product/category';
                                   } elseif (isset($this->request->get['manufacturer_id'])) {
                                           $this->request->get['route'] = 'product/manufacturer/info';
                                   } elseif (isset($this->request->get['information_id'])) {
                                           $this->request->get['route'] = 'information/information';
                                   }
                           }
                            else {
                               $query = $this->db->query("SELECT * FROM " . DB_PREFIX . "url_alias WHERE keyword = '" . $this->db->escape($this->request->get['_route_']) . "'");
                               if ($query->num_rows) {
                                   $this->request->get['route'] = $query->row['query'];
                               }
                         }
                           if (isset($this->request->get['route'])) {
                                   return new Action($this->request->get['route']);
                           }
                   }
           }
   
           public function rewrite($link) {
                   $url_info = parse_url(str_replace('&amp;', '&', $link));
   
                   $url = '';
   
                   $data = array();
   
                   parse_str($url_info['query'], $data);
   
                   foreach ($data as $key => $value) {
                           if (isset($data['route'])) {
                                   if (($data['route'] == 'product/product' && $key == 'product_id') || (($data['route'] == 'product/manufacturer/info' || $data['route'] == 'product/product') && $key == 'manufacturer_id') || ($data['route'] == 'information/information' && $key == 'information_id')) {
                                           $query = $this->db->query("SELECT * FROM " . DB_PREFIX . "url_alias WHERE `query` = '" . $this->db->escape($key . '=' . (int)$value) . "'");
   
                                           if ($query->num_rows && $query->row['keyword']) {
                                                   $url .= '/' . $query->row['keyword'];
   
                                                   unset($data[$key]);
                                           }
                                   } elseif ($key == 'path') {
                                           $categories = explode('_', $value);
   
                                           foreach ($categories as $category) {
                                                   $query = $this->db->query("SELECT * FROM " . DB_PREFIX . "url_alias WHERE `query` = 'category_id=" . (int)$category . "'");
   
                                                   if ($query->num_rows && $query->row['keyword']) {
                                                           $url .= '/' . $query->row['keyword'];
                                                   } else {
                                                           $url = '';
   
                                                           break;
                                                   }
                                           }
   
                                           unset($data[$key]);
                                   }
                           }
                           else {
                           $query = $this->db->query("SELECT * FROM " . DB_PREFIX . "url_alias WHERE `query` = '" . $this->db->escape($data['route']) . "'");
   
                           if ($query->num_rows) {
                               $url .= '/' . $query->row['keyword'];
   
                               unset($data[$key]);
                           }
                      }
                   }
   
                   if ($url) {
                           unset($data['route']);
   
                           $query = '';
   
                           if ($data) {
                                   foreach ($data as $key => $value) {
                                           $query .= '&' . rawurlencode((string)$key) . '=' . rawurlencode((string)$value);
                                   }
   
                                   if ($query) {
                                           $query = '?' . str_replace('&', '&amp;', trim($query, '&'));
                                   }
                           }
   
                           return $url_info['scheme'] . '://' . $url_info['host'] . (isset($url_info['port']) ? ':' . $url_info['port'] : '') . str_replace('/index.php', '', $url_info['path']) . $url . $query;
                   } else {
                           return $link;
               }
       }
   

   }

But not working is that of version problem or else?

3. I also tried this using htaccess but not working.