If you have 10 cats and nine have black stripes, it doesn’t mean that 90% of cats have black stripes. That’s just what you’re seeing in your furry household. Academic research doesn’t work like that. It uses larger samples and calculates probability so that the margin of error is known. So when university research says several things are connected then you can assume there’s something going on. Sadly, a growing body of hard evidence suggests that well-being and happiness among young people isn’t helped by mobile phones and social media. The opposite seems to be true.
FOMO means Fear Of Missing Out. The 2018 research by Hunt, Marx, Lipson and Young found that missing out was actually a good thing when it came to social media; limiting its use reduced social media users' loneliness and depression. Less than half an hour a day finding out what Andrew Tate had for dinner made people happier. More than that and it made them sadder.
You can find the research here: https://guilfordjournals.com/doi/abs/10.1521/jscp.2018.37.10.751.