Tiered link building helps boost your website’s authority by layering links....

https://bizzmarkblog.com/what-anchor-text-should-i-use-for-tier-2-links-pointing-to-tier-1/

Tiered link building helps boost your website’s authority by layering links. Tier 1 links point directly to your site, giving it strong, high-quality signals. Tier 2 links support those Tier 1 links, making them more powerful and natural