Links for the search engine, which is better?

Question

Search Engine Optimization

Hello!
There is a site example.com without https and is not going to move anywhere.
Is there a difference for search engines between these links that are on the main page?

<a href="http://example.com/catalog/">Catalog</a>
<a href="/catalog/">Catalog</a>

Found an SEO freelancer, he says that the link http://example.com/catalog/for the search engine is external - therefore this is bad.
Is he telling the truth, and how significant are the differences?
I will not give up links where you can read about it.

Answer 1

For search engines, there is no significant difference. The freelancer is talking nonsense, because it's about the same host - example.com.
Relative (/catalog/) is more practical in terms of changes on the site, for example, you decide to change the address structure and you do not have to change internal links.