As an early 90’s millennial, I’ve never noticed a “gen z stare” as described in news articles like a “blank face that shows lack of social skill or ability to think”. The only times I’ve witnessed it happen and seen the older person accuse them of “gen z stare” is when the older person says something off hand or dumb but isn’t self aware enough to realize they’re being weird. Hell, I’ve given people a blank face countless times because I was taught it was better to say nothing at all sometimes. Especially when it came to talking to older people at work.
I remember when I was 16, some middle aged guy at work accused me of having no personality. In reality, I kept all conversations short as possible with him (like almost everyone in the store) because they were casually racist and misogynistic.
I think there is a case that could be made for ‘screen time’ having some kind of impact for how someone might come to value the presentation of persona for the sake of others comfort.
Like if you spend less time in person-to-person interactions, its might mean you won’t value it enough to constantly keep it up.