Manual Steering Kickout Calibration is steps 4 and 5 of the SteerCommand Z2 calibration routine. It is the very first physical calibration that is done and happens before the Wheel Angle Sensor Calibration that you are having issue with. See Pages 11-12.

https://portal.agleader.com/community/s/article/6102?language=en_US

When you are on the main SteerCommand Z2 Settings menu, push the "Full Calibration" button. Since you have already tried a calibration on this machine, you will get a prompt asking if you want to continue with the current calibration, or start a new one. Select start a new on. This should allow you to go through the Steering Kickout Calibration again. When you do, take the Setpoint slider and set it higher than seems right. Then proceed with your calibration. If the machine then calibrates you can adjust in back down from the Steering tab on the Run screen later.

Setting the Kickout well higher than I would want for actual use during calibration is part of my SOP for calibrating Z2s and SteadySteers. I then fine-tune the setting later when test driving the vehicle.