How to protect children from online violence?

Children are endangered on the Internet in various ways. Most often, it is a mockery by real-life acquaintances, or by acquaintances from social networks. The greatest danger is posed by people who misrepresent themselves, but children often know how to misrepresent themselves so that they can watch content that is not intended for children.
Many social networks ask for various information when registering users, including the year of birth. When entering this information, many lie, enter false information in order to be able to present themselves as children for easier access to other children. And many children do the opposite.
This problem of false registration of the year of birth when registering on various networks could be prevented by program analysis of the user's face.
There are programs that can change the image of a person's face by creating a new image of the same face as it will look in 10 or 20 years, or as the face looked 20 years ago. This program could easily be customized to reveal how old someone is in front of a computer or cell phone screen.
Many applications use a face image as a password to log in to a mobile phone, or to log in to an application. This app could be linked to an app that estimates a person's age per person, and together they could estimate the age of a person handling a device every few minutes. Based on the assessment of age, the application could determine whether it is a child or an adult.
Based on that, it could prevent children from watching adult content, or use applications that are not intended for children.
Another possibility is to warn children about the age of the person they are communicating with, who presents himself as younger than he really is.
In order for the program not to jeopardize the user's personal data, the actual age data should not be remembered and linked to other user data, but should only be used for current actions taken by the user operating a computer or mobile phone.
If a user is communicating with a child and has turned off camera access, or if the device does not have a camera, then the app should assume it is an adult.
If a user wants to watch content that is not intended for children has a camera turned off, or if he does not have a camera, then the application should assume that it is a child, and prevent access to content that is not for children.
This application could also be used by advertising agencies to send ads tailored to a particular user's age. In order not to send advertisements to children, the law should prohibit the sending of advertisements to persons recognized by the application as a child.