Discord is for people over 13 years of age in many countries, yet there are many minors there. It is not working.
I’m not saying anything about specific services, only that there is a legitimate concern which can’t simply be dismissed without reason.
I am not sure I meant to reply to you, to be honest. It is an issue but so far the solutions are terrible. Outsourcing parenting to the Government or companies is also meh. I am sure there are parents who know of ways to reduce screen time for their children, it ranges from installing a program that does not let you on a website or start another program until and unless this and that, or take the phone from the kid's hand and go for a walk or study, whatever.