You want a router that will not let those wifi devices reach the internet or contact any other device on your network except allowed devices.

For any device that needs to connect to the internet, you want to be able to use dns and ip block lists at the very least.

These changes are on my todo list. Tvs especially need to be quarantined. They scan your network to datamine and try to report your conversations to the tv manufacturer.

The next step is root the tvs and clean off as much junk as possible.