autofocus – Does the number of phase detect auto-focus points affect focus accuracy in mirrorless cameras?

Does the number of phase detect auto-focus points affect focus accuracy in mirrorless camera? And if so, how and why?

I am considering burying either a Nikon Z6 II or a Z7 II. They have 273 and 493 AF points respectively. For comparison, the Sony A7iii has 693 AF points, a lot more. I have read/heard that the Z6 struggles a bit with focusing the iris of the eye. Does this have anything to do with how many AF points? Perhaps less focus points means a lower chance the point will be in the right position on the subject?
Or maybe the contrast detect will work together with phase detect and the issue is not the number of points?

I will appreciate any informed answers.