I've spent a fair chunk of career designing/building installed audiovisual systems. Displays devices are what terrify me most from a security perspective (and i

I've spent a fair chunk of career designing/building installed audiovisual systems. Displays devices are what terrify me most from a security perspective (and it's a low bar in that world). They should never be network connected. Ever. It doesn't matter if they are a domestic or commercial device. Consider their usage in emergency response centres, situation rooms, infrastructure monitoring, meeting rooms in government offices, boardrooms at publicly listed companies, trading desks, or peoples homes as their source of news. They have access to every pixel shown. They'll also likely have a full audio feed even if audio is passing through another system. You can have all the security control that you like on upstream systems, strong integrity guarantees, and comprehensive validation of that. This is the device where you are most open to exfil or tampering before it's shown to someone. Even if the vendor isn't the one trying to actively exploit you they're almost universally running some form of incredibly dated, unpatched, and unhardened OS that is riddled with nightmare material vulnerabilities. Don't even put them on your IoT/untrusted network. If you need to control them, use CEC/DDC or a serial connection. Preferably unidirectional.