My eyesight’s rubbish. I learn very little from looking at people’s eyes. I almost never remember eye colours. It just doesn’t register because I “don’t see it”.

I have to make a special effort to make eye contact, and when I do I feel like my “trying to see better” habits and postures make others uncomfortable. I’ve no idea what “normal eye contact” feels like.

I might also have some autism traits (I’m a coder, after all), so that feeds into it.. but even if I wasn’t coder/austistic, I’d be struggling in this domain.

I offer this as anecdata for your “everyone is different” suggestion.