So there was a point where I was understanding what I needed, but I've just found some more stuff which has opened a can of worms and now lost again.
I have a Denon x3300w AVR which has multi input and dual output. I'm pretty sure everything needs to run off of the main HDMI 1 output as if I have both HDMI outs used, it defaults the resolution to whatever is lowest.
I mainly use a Nvidia Shield TV PRO to watch Netflix, Amazon Video and Plex, all in 4k HDR. I also have a Nintendo Switch going into the AVR.
I was looking at looking at this video and this video as I didn't have to use a HDMI2AV convertor and remove some stuff out of the setup. The first video he's using an Arduino Nano to control the LEDs, the second just the RPi. what's the difference between using the Arduino Nano and not?
I see people are saying about the HDFury to playback HDCP and HDR, I found this forum post Ambilight with RPi4, hdmi grabber and Denon AV-reciever which uses feintech splitter and the XOLORspace S104 from this post Multi-HDMI Devices Setup | 4k 65 inch TV using Hyperion. Are these the same thing and would get full quality to the TV?
One other thing I saw was and EDID emulator which I believe I plug one into each HDMI output, which essentially tricks/forces the receiver into displaying the same signal through both outputs, output 2 going to the Raspberry Pi. Is this worth looking into?
What are the differences between WS2812B and APA102 LED strips?
Any other information that would be worth knowing?