Redirect the single product page link to the shop page

You can try using template_redirect action hook to check if the current page is product page and after that, you can redirect the user to your shop page.

Paste this code into your functions.php

add_action('template_redirect','custom_shop_page_redirect');
function custom_shop_page_redirect(){
    if (class_exists('WooCommerce')){
        if(is_product()){
            wp_redirect(home_url('/shop/'));
            exit();
        }
    } 
    return;
} 

I have not tested it, but hope it will work for you.