So, if this is possible with fixing/disabling one axis, do I just need to disconnect the motor or also the encoder of this axis?
If I just disconnect the motor, doesn't the controller sense an error because he is not getting to the correct position of the axis?
"So, if this is possible with fixing/disabling one axis, do I just need to disconnect the motor or also the encoder of this axis?"
Only disconnect the motor. If you also disconnect the encoder, you will get an error code and the remaining two axes will not initialize.
"If I just disconnect the motor, doesn't the controller sense an error because he is not getting to the correct position of the axis?"
Probably. But when I disconnected the motor and checked it on the bench, there were no codes, the other two axes initialized, and the gimbal seems functional other than no YAW movement.