csis01 You can't cast to it without connecting it to a network.
Wi-Fi-to-HDMI dongles (e.g., Chromecast) do exist. Connecting a "smart" TV to HDMI is not a large increase in attack surface against the TV. Might the TV compromise the Chromecast over HDMI? In theory, but I'd rather risk that than just connecting the TV to my network. In a sense I'd prefer to trust Google's dongle firmware than the TV's firmware.