Exactly. It's optional... as long as ypu don't plan on using internet.

The way the iPad has it seems OK, where you can disallow apps, websites and set time limits.

You're right. It's INCREDIBLY simple.

And I'm saying this as a systems engineer. I do this for a living.

I would go a step beyond and just make it a mandatory screen as part of setup:

Will this account mainly be used by an adult, by a teenager, or by a child?

I think the "teenager" would allow a little more granularity in parental control, but the "teenager" would legally be treated as a minor.

And you mandate that browser manufacturers be able to read that as part of the account information, but not forced to provide it to websites.

And you mandate that websites be forced to put in place restrictions that prevent adult websites from being provided to children or to computers that don't identify the user as an adult or as a child.

Restricting on the computer manufacturers' ends is the wrong way to do it. Restrict on the websites' end.

This would be simple. This would also not address the fundamental issue which is identification of bots vs. humans which are quietly destroying the online advertising industry (which, yeah, good riddance), which is what motivated Meta to lobby for online age verification to begin with. So it would fulfil the official purpose of age verification, but not it's real purpose