What's more secure than? when showing user id data

So here I am playing again with CodeIgniter and I tried modifying my User controller and some private pages and I just realized that when accessing to pages like "cart.php" I can do this in order to show their cart( of current the logged in user).

Controller

PHP Code:

public function cart($id)
    {
        
        // Check Login
        if($this->session->userdata('user_id') != $id) {
            // otherwise redirect to...
            redirect('store/index');
            
        }

        // Load Library
        $this->load->library('cart');
    
        $data['title'] = 'My Cart';
        
        $data['cart'] = $this->Store_model->get_cart($id);
                    
        
        // Load Template
        $this->template->load('public' , 'default', 'store/cart', $data);
                
    } 


Model:

PHP Code:

    public function get_cart($id){
        
        $this->db->where('user_id', $id);
        
        $query = $this->db->get('ci_cart');

        if($query->num_rows() > 0){
            return $query->result();
        } else {
            return false;
        }    
                
    } 


and the one I just realized which I think looks nicer to avoid having urls like(notice that I don't pass vars):

Code:

"example.com/cart/1/kirasiris"

new Controller function:

PHP Code:

public function cart()
    {
        
        // Check Login
        if($this->session->userdata('user_id') != $this->session->userdata('user_id')) {
            // otherwise redirect to...
            redirect('store/index');
            
        }

        // Load Library
        $this->load->library('cart');
    
        $data['title'] = 'My Cart';
        
        $data['cart'] = $this->Store_model->get_cart();
                    
        
        // Load Template
        $this->template->load('public' , 'default', 'store/cart', $data);
                
    } 


new Model function:

PHP Code:

    public function get_cart(){
        
        $this->db->where('user_id', $this->session->userdata('user_id'));
        
        $query = $this->db->get('ci_cart');

        if($query->num_rows() > 0){
            return $query->result();
        } else {
            return false;
        }    
                
    } 


which just create a simple url like:

Code:

"example.com/cart/1/kirasiris"

So yes, I'm just wondering what is the best approach. If somebody can tell me I will be very grateful

I do Front-End development most of the time 

Is the Cart controller for open shopping basket?

Assuming one client will ever only have one basket open at any time, you could just use user_id from session, and fetch any (well, one) open carts where user_id = session user_id, and there's no need to send cart IDs back and forth via URL.

Alternatively, if carts do have IDs, you can also use session user_id with query without putting it on URL:
SELECT * FROM cart WHERE id = ID from URL AND user_id = user_id from session.

Having user_id on URL and then in session I don't think adds much to security, it's kind of checking one thing to itself?