Does the TMCM-1260 support robust position control? e.g. if I manually turn the motor axis, would this one come back alone to the target position?

The TMCM-1260 is an open loop module, thus it won't come back alone to the target position. It has a safety function which stops it if the error is too big. Position control with this product will be open loop with an accuracy of up to 256u Step.