Ok, I was a big Hyperion fan but, my setup is complex, I'll go through it....
For the longest time, I had its setup like this. My AVR supports only HDMI 2.0b on this setup I have 2 HDMI monitor outs. I used to use this with Hyperion (PI 3b with a 4K 60hz capture device). Then the Series X and PS5 came in the picture with HDMI 2.1, my AVR does not support HDMI 2.1 but, my TV does.
The AVR does deal with DVR and my Home theater PC so the HDMI switching is needed here.
At this point running new consoles direct in the TV, then I was using ARC to run Atmos Audio back to the AVR, this worked fine but as you guess, my Hyperion setup didn't work with HDMI 2.1 devices. During this time, I decided this would never work with my setup (a lack of HDMI 2.1 devices for quite a wile) and moved to a $80 Govee camera setup and I HATE IT.
Towards mid last year ARC just failed completely, something broke, spent like 3 months troubleshooting this and with 0 results. From that point could only get audio through the TV, no Atmos, nothing through my sound system.
Now, I found a HDMI 2.1 Audio extractor. This solved the ARC failing problem. HDMI 2.1 devices run to this extractor, a passthrough cable goes to the TV, then an Audio only HDMI cable goes back the AVR, so I can get Atmos and other higher audio formats.
Everything is completely macro'ed out via a touch screen remote, I can do complex wiring things and as long as it could be controlled via IR, you only hit one button to make the magic happen. I don't care about the device as long as it can be IR controlled; I can make it disappear.
IN a nutshell, HDMi 1 on the TV gets AVR stuff and HDMI 2 gets 4K 120hz sources...
What I was thinking... a HDMI 2.1 switch that is IR controlled, run the output from the Audio extractor on port 1, and AVR to port 2 (macro'd out on the remote), the ouput here would go into HDMI 2.1 Splitter, this pass through perfectly HDMI 2.1 devices but, one output would be 1080p 120hz, then go to Hyperion with a PI driving accurate LEDs.
I think all I really need is a device that can take a HDMI 2.1 signal, OR a 2.0b (1080p @ 120hz is within spec on HDMI 2.0b) and capture video to import into Hyperion on a PI.....
I am creative to find solutions for other things as you can see but, I want to get back into Hyperion for accurate LEDs...