Permalink of any product by ID

get_permalink( $product->get_id() );

are you kidding me? this function does not return the url with /shop/ or /product/. The function does not work.

Works for me. I wrote this to test it:

<?php
  add_action ('woocommerce_single_product_summary', 'test', 80);
  function test() {
    global $product;
    echo get_permalink( $product->get_id() );	
  }

It prints the page url after the meta data on single product pages:
https://www.my-domain-here.co.uk/product/hydrofoil/
In this example, “hydrofoil” is my product, and I’ve overwritten my domain name.

I need to call it on the admin page. does it work?

Should do. The thing to do is make sure your code has made the $product object correctly.