A quick google search showed me you’re able to enter a secret menu mode, however, there’s no enable/disable option for HDR. Have you found a way to turn HDR off on the TV so that streaming services (e.g. HBOMax) won’t automatically use it?
For some “4K HDR” movies I notice I have to set the gamma to 1.8 for certain scenes to be visible at all, even in a completely dark room. It feels unacceptable to HAVE to enable HDR.