I won't make any comments about this test, I'll just post the article for your consideration.
https://petapixel.com/2017/09/27/nikon-d850-autofocus-tracking-not-good-d5-test-finds/
https://petapixel.com/2017/09/27/nikon-d850-autofocus-tracking-not-good-d5-test-finds/