as much as a pain in the ass as it would be, i think the best set up is having the lists curated per state. red states can ban stuff for children they don't like, and blue states can ban stuff for children they don't like. it's not a perfect system, but that's pretty much how these kind of things work now. it may be naive, but i would hope that having a chokepoint for minors' access to the internet would at least make it much, much harder for groomers to have Discord chats or Roblox levels that draw in children who then get spammed by porn or grooming messages
it's not a magic bullet that will fix all problems. but the purpose is to have some kind of enforceable, concrete divide between minor spaces and adult spaces on the internet. the system i'm thinking of isn't just to stop minors from accessing porn, which seems to be a blind spot for some people. what really needs to happen is breaking down the idea that we have apps like Discord where adults and children use the same app and can easily intermingle in the same places
the next question is, "how do you prevent the adults that are required to janny these spaces from grooming the children themselves?" well, unfortunately, that's a problem you face with any kind of place where children are present. ultimately having a stringent hiring process, filtering out the generic groomers who will spam porn at kids out in the open, and making it so a pedophile needs to be really, really sneaky to groom a child is the best that you can do