I feel like all of these laws are being designed backwards. Content providers, like MPAA films, should have to identify what sort of content they are providing. Then I can give my kids a device configured to allow some or all of that at my discretion. Requiring my kids' devices to advertise their age (or their age "bucket", as if that was a meaningful difference) to protect them is not doing me or my kids any favors.
This isn’t for the protection of kids. It’s for the protection of profits by surveillance capitalism.