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

https://research-wiki.win/index.php/How_Do_I_Choose_Landing_Pages_for_Tier_1_Links%3F_A_Strategic_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