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

https://bizzmarkblog.com/tiered-link-building-campaign-checklist-a-week-by-week-guide/

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