Some things there just don't add up. HDMI is a digital AV cable. It has nothing to do with internet/network access. VPN can be used to securely connect LANs across the internet, or to obscure one's origin, but neither helps with the snooping TV. The thing will still connect to whatever server is programmed into it. (And the same applies if the TV is used as a browser. If it is sending that traffic to its mfg, a VPN will not make any difference.)
An outgoing filter on the network may (if possible to figure out the services it talks to, those comms can be blocked,) but then it may just decide to go off and sulk.
And VPNs are a can of worms all their own. She may find she's still the product, only to a different set of predators.
An outgoing filter on the network may (if possible to figure out the services it talks to, those comms can be blocked,) but then it may just decide to go off and sulk.
And VPNs are a can of worms all their own. She may find she's still the product, only to a different set of predators.