hdrToggle VS HyperHDR

Install an hdr command toggle like https://github.com/kurbaniec/hdrToggle and add it as pre command of another app in sunshine. You can also use something like nircmd to change the host display resolution. Now when connecting from the steamdeck, chose the non hdr application

If you have an nvidia card, the api makes things much easier. https://github.com/kurbaniec/hdrToggle

You can DIY your own with a IC-based RGB/RGBW strip and a rPi or x86 PC + ESP microcontroller using software like Hyperion or HyperHDR, combined with WLED.

This page https://github.com/awawa-dev/HyperHDR/wiki/Level-Shifter shows that a level shifter (3v3 to 5v) is needed for your lights.

If you're interested in a raspberry pi option using an hdmi splitter https://www.hyperhdr.eu

I spent a lot of time looking into this. Didn't want to lose HRD to implement Hyperion. I found the HyperHDR fork. Which will convert HRD signal to SDR and works really well out of the box. only thing I had to update was to turn the brightness down in the capture settings. Found a HDMI splitter on Amazon that handles CEC pass through. I lost Dolby Vision, because I couldn't find a splitter that will downgrade dolby vision to 1080p for the capture card. But I had to be honest with myself, I can't tell the difference between Dolby Vision and HDR 10+. Now I have an ambient light solution that allows me to keep HDR without dropping big bucks on something like HD Fury. Very Happy, works with HA still too.