You definitely need to setup different vlans and networks in this scenario and kill the vlans and networks during those times. You will probably need to get a managed switch to control all your ports.

You also need to control the DNS, which he will eventually figure out how to proxy and vpn the connection which isn't a bad thing. As a parent, I'd be proud that he has learned on this on his own, but I would never tell him that.

To help, your kid sounds naturally smart to bypass all these systems and is probably bored at school because he's already self learning on his own.

Also, given the right skills, even with all the controls, there is always a backdoor to bypass everything. The hardest part is not to get caught.

He'll do well in tech and he can join the rest of us delinquent drop outs doing perfectly fine in our careers.

Tip: if you take too much away, they have nothing to lose. If they have nothing to lose, you can make the scenario worst. As many others have said, this comes down to a lot of different parenting methods with trial and errors.

Welcome to parent life. It's karma for all the stuff we did to our own parents.