Zend certified PHP/Magento developer

Does Magento keep short URL live when Use Categories Path for Product URLs is YES?

We have set our store to be Use Categories Path for Product URLs: Yes – in m2.4

And so the product pages, are www.mydomain.com/category/sub-category/my-product

But if I remove category and sub-category, so I am left with the orginal SHORT URL like this: www.mydomain.com/my-product

So I am confused, as I thought choosing to have cateogies in URL would remove the shorter versions?

Doesn’t Magento automatically redirects from short to the longer format URL?

If that is the case, there appears to be a lot of Duplicate SEO issues? Or Maybe I am just misundersanding the system?

any help or pointers would be great