That's why I suggested kernel enforced security (simple syscall) that applications could implement and are incredibly hard to spoof / create tools and workarounds for, but I got downvoted to hell.

Permission restricted registry entry (already exists) and a syscall that reads it (already exists) for windows and a file that requires sudo to edit (already exists) and a syscall to read it (already exists). Works on every distro automatically as well including android phones since they run the linux kernel anyway. Apple can figure it out and they already have appleid.

For linux we have the users and groups concept, the distro can add an adult group and when you give your child a linux a device and create the account you would just chose adulr or minor , or enter a birthdate. No freedom lost for the geeks that install Ubuntu or Arch for themselves and we do not need some extra hardware for the rare cases where a child has access to soem computer and he also can wipe it and install Linux on it. Distro makes can make the live usb default user to be set as not adult. Good enough solutions are easy but I do not understand why Big Tech (Google and Apple) did not work on a standard for this. (maybe both Apple and Google profits would suffer if they did)