I think you were getting trolled. The auto focus from day one has been excellent and has only gotten better as they have been releasing updates. I own one and don't really care to take part in forum mudslinging, but I would seriously question anyone who thinks that the autofocus is anything but good (for MILC).

There are issues with AF, but that goes for Sony and Canon flagships as well. Overall, Nikon probably still is third in AF performance, but it's a very, very close third with the Z9. You do however need to know how to use the camera. A lot of the complaints about the AF online are from people who pick it up after using a much simpler camera like a D850 and expect to be able to get the most out of it without reading the manual or conducting tests.

Excuse me, a much simpler camera like the D850? I have an ebook here explaining its auto focus system, it's 200 pages.

Yeah, not saying it's a simple camera, but the AF system is simpler.

"a lot of people were complaining about the autofocus"

A lot? This must mean you get your info from Youtube grifters. Every serious reviewer has praised the Z9 for having world class auto focus capabilities that defy belief. People are panning tiny birds in flights and it just keeps hitting it.

The only criticism is that Sony has a tiny notch up in very specific situations, yet that gap is rapidly shrinking. We're talking really marginal differences here.