You have probably wrong steps per mm, delta radius and diagonal rod length. Wrong delta radius and diagonal rod length together can partially compensate for wrong steps per mm in XY direction.
Level the bed first, it must be leveled at least at these points:
* as near to each tower base as possible,
* as far away (across the bed) from each tower as possible,
* in the bed center.
Your calibration object is too small to show XY error. But you probably cannot even print an object which is e.g. 0.5 mm tall but covers whole bed (because your bed is not leveled everywhere).
Level the bed first, it must be leveled at least at these points:
* as near to each tower base as possible,
* as far away (across the bed) from each tower as possible,
* in the bed center.
Your calibration object is too small to show XY error. But you probably cannot even print an object which is e.g. 0.5 mm tall but covers whole bed (because your bed is not leveled everywhere).