I don’t think kids should be on the internet (public WAN) alone at all, so easy for me. They could get larger whitelists over time as they approach 18—no sites where they interact with adults.
Without a working internet connection, you can simulate network setups, but not the real deal.
A teen at SDF could learn much faster with people with wisdom than by themselves.
They can be guided in a much easier way.
Hint: I didn't got internet at home until very late. And, back in the daw I knew a lot in some areas,
such as drivers under GNU/Linux, adapting basic BTTV drivers and so on, but severely
lacking in others, because there was no proper information to start with.
I used LANs half a decade before connecting to the wider net. SBCs and VMs are much greater resources than I learned on. Routers are cheap, I just set up a dynalink with openwrt for $75.
No one is asking teens to set up a production kube cluster. There’s so much to learn—they’ll be fine.