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

https://dibz.me/blog/strategic-insights-crafting-an-effective-tiered-link-building-campaign-959

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