As someone with the OG steam deck, and an HDR TV that my main PC and PS5 are hooked up to, I have issues all the time when streaming HDR content to the non HDR display on the steam deck. It tries to convert the image to standard dynamic range, but just blows out the whites and crushes the blacks. I always gotta remember to turn HDR off on my PC before streaming, but it would be really nice not to have to do that.