Root Domain or Subdomain Link *Which helps in SEO *

In these days people are started posting articles on various sites to get a ******** contextual backlink.
But some sites are available to post on root domain and some are on subdomain.
like this,
example.com/your-post
or
community.example.com/your-post

Do you think both of these rootdomain and subdomain links are useful for seo to rank and build authority.

Note: Expecting answer from an experience seo person. And when answer please mention the reason behind your point.

I hope it will help many webmasters and business owners.

Yes, some of the top editorial sites and EDU sites publish articles on their community page. So it will be good to have a link from the subdomains that represent top sites but you cannot expect the same value you get with the main page.

It will have decent metrics too, can be used as a diversification factor for your backlink profile.