1) When buying a device, store employee could program user's age range.

2) When configuring a device, parent may toggle "child mode" checkbox to switch the device into "child mode", protected with a password or fingerprint.

3) The tokens, containing a private key (same for all tokens) can be sold in liquor stores to adults only. This token could confirm the age without a passport.

It is interesting that is US (unless I am wrong) you can vote and change the government without a selfie and a passport, but you need them to use Reddit or Discord.

> but will require better/easier/free tools and education to help lock down different categories of harm.

There should be a single big "child mode" checkbox for normal people and "configure" button for 1% of geeks. Most people do not need tools and have no interest in configuring allowed categories.

> Everything I've seen is ineffective or can be compromised

Selfie/passport also can be compromised by asking a friend/older brother/parents to verify your account. Especially if you have a poor adult friend with alcoholic dependency in dire need of a new portion.