Roku 4K UHD HDR setting is too dark and washed-out
I've got a six month old 9102R Streambar and I'm having trouble with certain resolutions being too dark to watch. I've had one Roku or another hooked up to this TV for years and only noticed a problem today, but I haven't changed anything and I can't believe I've lived with it all this time. I ran into the problem for the first time today when I went to stream House of the Dragon on HBO and the picture was too dark and washed-out. I played some content on Prime and Netflix as well, and the higher-resolution shows behaved the same way. Too dark with the Roku set to 4K UHD HDR, but just fine in 4K 60 fps. Auto detect picks 4K HDR10 at 60fps. So:
Roku set to 4K UHD HDR (says "4K HDR10 at 60 FPS" at the bottom): HBO 4K UHD show, Prime HDR UHD show, and Netflix Ultra HD 4k all too dark and washed-out to watch.
Roku set to 4K 60fps: All of those exact same shows are OK to watch.
TV is a Sony Bravia KD-65X7000E with Roku plugged into HDMI 3/ARC which is set to "Enhanced". Sony spec says 4K UHD 3840x2160 and HDR compatible. Roku cable.
I believe that I got the HBO, Prime, and Netflix format references correct above, but there's no question that on HBO, House of the Dragon with the Roku set to 4K UHD HDR is unwatchable, but at 4K 60fps it's just fine. What am I doing wrong?