Is it better "nofollow" or "dofollow" links to external social pages?

Doesn't matter. All the links are same now.

Dofollow links are those links which do not contain Rel=”Nofollow” attribute. These links have the potential to improve the ranking & credibility of your website in search engines. If a webmaster is linking back to you with this type of link, then both Search Engine and Humans will be able to follow you.
Method 1 Using Source Code
Right-click on the document you wish to inspect.
Select “View page source”. Alternatively, right-click on the link you wish to inspect. Click on “Inspect ele

do follow is better on no follow pages because do-follow link forward one link to another link.

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