Limit Frame Rate
If you have an iPad Pro (10.5-inch) or iPad Pro 12.9-inch (2nd generation), you can set the maximum frame rate of your display to 60 frames per second. Go to Settings > General > Accessibility > Display Accommodations and turn on Limit Frame Rate.
Yeah, I was wondering why is this option in Accessibility too.
As a person with known cases of motion sickness from electronic devices, ProMotion made it better for me actually! (And this is why I sold off my 1st Gen quickly to prepare for the Gen 2 despite knowing that I will incur losses)