I wonder if any of these studies distinguish between people who use screentime more productively. I use my phone on a morning for Duolingo and logging my workouts. That's quite different to doomscrolling, but I still wonder if it's good or bad. There's also the category of people who stew infront of a TV all day - it's unsurprising that these people will have lower cognitive functions, but is that because they don't…
I mean I'm guilty as well, I often browse reddit mindlessly, often r/all which opens up the floodgates (although it's not really 'all' anymore, it used to include porn as well and subreddits can opt-out I believe).