Any internet functionality will come from a device I trust and control, with only the display portion handed to Spysung.
Many older cables didn't connect it, or grounded one of the pins (*because it had been used as a plug-detect pin), but since devices started actually using it, cable vendors started wiring it. The extra pair doesn't make the cable much stiffer, but leaving it out had made them ever so slightly more flexible.
Many devices don't support it, but some newer video cards install an Ethernet device when you load the driver, so they do. And some TVs do, of course. So if such a card and such a TV are connected with such a cable, voila! An connection you might not even realize is there. Your formerly-isolated TV is no longer isolated, assuming the video card driver installer did something like enable bridging to that ethernet interface.
There are a few ways to avoid it. First, don't install that driver if your video card prompts for it, or disable the device. Second, use a cable tester to verify that you're using a cable which doesn't connect the pins, which is gonna get harder if you need a newer cable that's tested to a higher bandwidth spec. Or third, open up the cable and bite the wires in half. It's tricky to know which pins those are; I plan to do it with an inductive "toner" probe connected to a breakout adapter.
(Unrelated: Some Ethernet switches used HDMI cables to connect each other for "stacking". This is just because the connectors are cheap, the cables are cheap, and they have a lot of high-bandwidth pairs. The switch makers could run more-or-less full backplane speeds over a short HDMI cable more cheaply than they could over a custom stacking cable. But the signals on the wires are not HDMI, they're more-or-less Ethernet on whatever inter-switch-chip format, probably QSFP or something, that needs a bunch of length-matched pairs.)
Is it possible to use something such as an HDMI splitter to accomplish the same thing, or can those pass Ethernet as well, and how would you be able to tell?
For any faults, HDMI is a typically good cable.
... that one could build an "HDMI Condom" that would strip those pins with an adapter. That would be more elegant than cutting the cable open ...
I use a "USB Condom" myself when I want to charge my phone at hotels or when I want to charge from my laptop and don't want to set into motion 150 phone/computer interactions.
Are there any particular brands I should be looking for?
Most Kogan TVs can be great dumb screens if you reach out to support for recommended colour settings and you use an external sound device (soundbar).
I want a 4K dumb panel, with HDR10 support. I saw the Kogan 55" JU8200, which from my browsing appears to be the latest model, and from my crude understanding of the specs would be decent?
Should I send an email through to support about it? To be honest, Kogan as a brand is so low-touch I didn't even think to contact them haha.
I honestly haven't seen many other Dumb™® TVs to even choose from, so I am sort of leaning towards either picking up the JU8200, or maybe just biting the bullet and getting a Hisense Series X for about twice the price, but with OLED panel.
The "smart" stuff in the Hisense isn't particularly smart from what I read and watched today, and can be mostly disabled, as its less intrusive than Samsung et al. I'd love to know if I'm wrong on that conclusion though!
EDIT: Oh, and I have a Yamaha 2-channel amp that I run the TV into, so no worries on the crappy built in audio of the Kogan TVs haha. Amazingly tinny, my current one!
Worst case I'll put it in my garage electronics/chemistry lab lol
It’s a pity more TVs don’t support this as it would be a great combination for me.