When pressing Z - or Z+for a longer time (about 3-4S), the Z axis will go down or up all the time, and it is normal to press Z - or Z+for a shorter time.

Analysis and troubleshooting:
This is the reaction delay. Check whether the Z-axis parameters are correct.
Solution:
In the manufacturer's settings, check the Z-axis parameters, mainly the maximum speed, takeoff speed, acceleration and emergency stop acceleration are not adjusted properly, and they are readjusted.