I wanted to test FW3.01 in advance of an agility event this coming weekend, so I sat in at a canine frisbee league on Saturday. From what I can tell, the new FW works very well. I had only one brief series that locked in on a spectator rather than the dog, which was a tiny fraction of what I shot.
I used WA Large and WA Custom (set to to max size) most of the time and had Subject Detection enabled the whole time.
One thing I noticed was that I didn't have much (hardly any) trouble with low-contrast dogs. Anyone that's shot dogs will understand the some are harder to get focus lock than others, but I didn't have any issues with any of the dogs, regardless of color / contrast. Perhaps is was just the grass was all dead making the "any" dog (or object) appear as contrast to the grass.
NIKON Z 9 NIKKOR Z 100-400mm f/4.5-5.6 VR S lens 400mm f/6.3 1/4000s 720 ISO 0.0 EV
NIKON Z 9 NIKKOR Z 100-400mm f/4.5-5.6 VR S lens 240mm f/6.3 1/4000s 560 ISO 0.0 EV
NIKON Z 9 NIKKOR Z 100-400mm f/4.5-5.6 VR S lens 160mm f/6.3 1/2000s 560 ISO 0.0 EV
NIKON Z 9 NIKKOR Z 100-400mm f/4.5-5.6 VR S lens 290mm f/6.3 1/4000s 1000 ISO 0.0 EV
NIKON Z 9 NIKKOR Z 100-400mm f/4.5-5.6 VR S lens 155mm f/5.6 1/4000s 560 ISO 0.0 EV
NIKON Z 9 NIKKOR Z 100-400mm f/4.5-5.6 VR S lens 210mm f/5.6 1/4000s 560 ISO 0.0 EV
NIKON Z 9 NIKKOR Z 100-400mm f/4.5-5.6 VR S lens 240mm f/5.6 1/4000s 450 ISO 0.0 EV
NIKON Z 9 NIKKOR Z 100-400mm f/4.5-5.6 VR S lens 185mm f/5.6 1/4000s 560 ISO 0.0 EV