We can do all of the above.
No, we cannot. At a societal level, we can't do any of it.
Protecting a child from content on the internet requires a massive invasion of the child's privacy. That degree of privacy invasion should not be granted to society in general. It should not be granted to the operators of a pornography site. It should certainly not be granted to the groomers.
The only place where that degree of privacy invasion is reasonable and acceptable is between parent and child. If you want to protect the children, you give parents the tools to regulate content. You don't provide those privacy-invading tools to the content providers and you certainly don't expect them to take a parental role over your kids, let alone your neighbors and yourself.