This is absolutely not just "bad parenting". When sending children to school they are now immersed in an online culture that is wholly unaligned with their best interests. There is no "good parenting" strategy that can mitigate the immense resources being poured into subverting their attentional systems for profit. Even taking away their smart phone is no solution: that requires their social exclusion from peers (damaging in itself for child development).

You can teach them how to use social media responsibly. Or allow them a phone but limit social media usage (though I prefer the first approach). It’s not like everyone is harmed, the same studies find a positive effect for a significant minority.