The youngest, about 7 I think, would come home after school and just watch a TT-like show on TV where it was just endless "scrolling" through short videos that appeared as though they were straight off TT/Insta. He was literally addicted to it.
Imagine someone producing/moderating that in a way to get kids to just continue to watch it non-stop.
My point is, you don't even need an app and age verification... this stuff is just right there on regular old TV.