Or… if it is truly about child safety and is not about building the surveillance-state, we can do one of two things:

1): Hold the parents responsible for allowing their children view NSFW and encourage them to use a network appliance like Firewalla to manage all devices from one place and to block all websites, downloads, and internet by default with a whitelist on the Firewalla mobile application to authorise specific things. That is the first and least invasive child safety mechanism that does not risk normalising or enabling the surveillance-state.

2): Make NSFW posted on specific websites, make people who post NSFW content SPECIFICALLY give their ID to the government for a permit that the government shall grant and companies check for validity, and allow people to apply for an NSFW permit that the government shall grant after an agreed upon age for companies to check for validity.

Edited to add Firewalla as a suggestion.