So both at set-up and now after the TV updated itself overnight to tvOS 11.3, it said my region uses a different refresh rate and wanted me to change it. Problem is, that refresh rate (4K HDR 50Hz) causes bad motion effects on Netflix. Also, I'm pretty sure my TV is 60Hz (per https://www.displayspecifications.com/en/model/3051574) like basically everywhere in the world because we're not in the age of CRT anymore. So why does Apple think that 50Hz is better for me when my TV is apparently 60Hz and performance is actively worse in 50Hz? When I manually changed to 60Hz my TV didn't make a fuss, supported it fine. And the motion issues went away (presumably because it was doubling 30fps source video in Netflix to 60Hz).