posts or custom posts child-URLS dinamically generated

Hi everyone,

How can I do to a have a post (or custom post) with a definite URL (e.g. https://www.test.com/category/post-name)
and a child-URL referred to a specific section of that post (e.g. https://www.test.com/category/post-name/sub-url)
without being obliged to create a specific post related to that child-URL?

E.g.

I have a post with link https://www.test.com/category/post-name originated by file content-product.php
and I want to have a child-URL like https://www.test.com/category/post-name/details originated by file content-product-details.php
that refers/recall only a section/portion of the post.

In few words is there a way to create the structure indicated? Or do I have to manually create for each post as many sub-post
as child-URL I want to have?