Some simple test to help diagnose issues: Is steering harder in one direction than the opposite?
Turn the wheel (motors down but not running) and turn the wheel all the way to one side. Now turn all the way to the other side and count the turns. Do the same test for the opposite direction.
Now turn fully to each side and put more force on the wheel. Eventually with sufficient force, the wheel should rotate more than initially. Repeat for opposite rotation.
With the wheel in the center position, turn the wheel slowly while looking at the motor(s) and the wheel to see what fraction of a turn it takes before the motors start to move. That should be a small fraction of a turn.
Do you have a single or twins. If single do you have an anode on the LU with a fin? If so, at what angle is the fin set to?
If you have twins, do you have fins on the tabs?
If you have not bled a system like yours before and this a new task AND you bled it by yourself, you probably didn't bleed it correctly