NPCs in Skyrim never shut the fuck up and prioritize staring at you rather than focus on what they're currently doing. Walk straight through to the market district in Whiterun and 3 - 4 NPCs will stop, gawk at you and quip their greeting line. No NPC Greetings changes the distance which NPCs will greet you or disable it altogether, but doesn't affect their unrealistic headtracking. This mod reduces the distance which NPCs will begin and stop headtracking for the Player Character, if you disable this entirely and NPCs will never look directly at you no matter the distance

Requirements
Skyrim Special Edition 1.5.97 or higher