I didn’t think any devices even adopted Ethernet over HDMI

Never been implemented. It doesn’t exist.

Cables support it but zero devices made it to the consumer market and both devices would need to support it for it to work. It’s a dead standard from another era at this point. WiFi speeds have become so significant that there’s just no reason for the additional costs that would be involved.

I admit if half of the people out there who bought smart TVs started refusing to connect them to the internet and bought streaming boxes instead there might be an incentive for TV makers to try it but no incentive for streaming devices to help them do it and at that point it’s just easier for TV makers to require an internet connection or the TV doesn’t work.