questions on backlinks

in order for your keywords to show up more often organically or for your site to be ranked higher, does a backlink from a popular root url matter more than a specific url?

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Let's say for the sake of this example, there is a website root url called www.fdjkasl;fdsa.com and my backlinks is shown on a subfolder called www.fdjkasl;fdsa/blog.com.

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The root url has a high Authority score (from semrush) but a low score on the subfolder. Does that mean that the backlink is weak?

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sorry very new to backlinks.

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Appreciate feedbacks from the experts