Are headshots inconsistent for anyone else?

Decided to start playing around with Mantis and Warlock because I enjoy supports that benefit from crits (former Kiriko player) and I can't seem to get a grasp on hitting headshots. Every hero seems to have a different head height that bobs and weaves based on the ability they're casting, half the cast can dash multiple times and models just feel kinda small?

Was wondering if anyone else was having these issues or is it just a skill issue on my part?