Tier 1 links are your direct authority boosters while Tier 2 links help them...

https://paxtonsnewdigest.iamarrows.com/why-do-so-many-sites-ignore-my-outreach-emails-the-truth-about-link-building

Tier 1 links are your direct authority boosters while Tier 2 links help them stay relevant. Using Ahrefs to monitor your backlink profile helps you see how these layers push rankings up without overdoing it