Buy a chrome cast, fire stick, or roku and stick it in your android TV that isn’t connected to the wifi.
The chrome cast, fire stick, and roku have their own privacy issues associated, but if they were running malware (outside of what we know of those services collecting and selling user data to advertisers) they would have bigger problems.
Don’t give your TV your wifi password, or an ethernet cable. Turn any cheap “smart tv” into a “cheap tv”. Use your other devices that you already ignored privacy warnings of trust and nobody loses anything.