When Nikon started shifting over from the screw-drive autofocus system of their regular F mount AF lenses to their AF-S system they started adding autofocus motors inside the lens itself. One of the key selling points at the time was that no matter which camera you were using, the lens would always rack from minimum to maximum focus at the same speed as the motor was in the lens itself.
Along comes Z mount with adapted F mount lenses and this didn’t hold true anymore, with them generally spinning slower (albeit achieving similar overall results due to the more advanced AF system). Not anymore, though. According to this video from photographer Dariusz Breś, Nikon seems to have gotten AF-S lenses spinning just as fast on the Nikon Z9 as they did with their DSLRs.