This is a nice idea, because it physically limits the place the child can call from. Even a very under-powered phone sets them free.

However, a new severely under-powered phone with no graphics or apps would probably meet the requirements of not being sucked into the grown-up world too early, and the kids can maintain their own contact lists.

And they'll grow super-fast thumbs like we had to in order to text :)

They cost about $50 but are still 4G.

Have you found a under powered phone that lets you lock down the Phone's incoming to an allow list?

That is the thing me (and most parent friends) want: freedom from spam calls and potential strangers.