What I'd recommend is research on specific behaviors taken by social media companies to determine which are shown to cause harms. Some of that is already done by the companies themselves. If, for example, infinite scrolling is seen as a practice that increases addiction to the platforms, a law can be passed that makes it illegal to implement infinite scrolling. A law like that is pretty easy to explain and understand. TikTok was called out for sending push notifications to children's phones late at night to drive compulsive consumption and disrupt sleep patterns. Laws can be passed to limit how many unsolicited push notifications platforms can send and during which hours. Laws like that focus on the actual problems themselves, regardless of which platform is doing it, or who they are doing it to.