Hmm. I didn't think about video settings on the Steam Deck. Since the screen can't even show full RGB, I'd hope they are not trying to use temporal dithering, but who knows. One of Linus Tech Tip videos basically said it's a tablet display.
KM You can check a display or lighting for its spectrum with a cheap handheld spectrometer. I got mine from eBay for $7 or so. My experience so far is that if the spectrum has thin distinct lines, then, in terms of brightness issues, it is potentially much better than White LED (which shows a rather continuous rainbow spectrum). AMOLED, Quantum Dot, CCFL, they all have those thin lines in common.
That's pretty fascinating! Thanks for sharing your findings. There just may be a chance the new Samsung OLED may be usable. I'm very skeptical though.