Getting $100$ backlinks from $100$ different websites is better for ranking purposes than getting $100$ backlinks from $10$ different websites because

search engines consider link diversity a sign of organic, independent endorsements of a website's content

if we get too many links from the same website, the search engines automatically assume we are buying those links

if the links come from $100$ different websites, those links are more likely to generate social sharing

the links from $100$ different websites will generate more traffic, and traffic is the most important ranking determinant