Lytmi Neo HDMI2.0 Pro Kit - $129.00USD ($60 off)

Of course had to check what it was

It's a good deal and these work very well for what they do, but I had one of these and ended up giving it away and getting a Govee Immersion kit that uses a camera instead.

The HDMI pass through works way better during the daytime / high light conditions when the camera will frequently mess up the colour accuracy, but in theatre style darkness the difference disappears and tying the backlighting to the HDMI signal has a bunch of drawbacks. The biggest showstopper for a lot of people is that it's impossible to use if you use your TVs built in smart tv setup since there's no HDMI signal to tap into.

If you have a single external input device (Chromecast / Apple TV / Roku / etc) it would work great, but if you have multiple devices (game console, Blu ray player, cable box, etc) then it will only work for one of them at a time unless you constantly switch cables or buy an HDMI matrix. And then on top of all that you have to deal with making sure the light box matches your HDMI capabilities. I.e. if you have an HDMI 2.1 smart tv box, connected to a tv that supports HDMI 2.1, this box will now limit you to HDMI 2.0 speeds.

I was skeptical of the camera approach at first but after sorting through all this with the Lytmi, it's what I would generally recommend for immersion lighting. It's nice to have a complete analog seperation layer between the TV/source and the backlighting setup.