Q: Extremely loose steering - screetching when parking and humming when full turn.

You have a newer type "electro-mechanical" type steering system. Noise is typically a sign of failure so obviously there is something wrong in the steering system. If there is abnormal, marked noise in the steering system, a mechanic would simply trace that noise to the faulty component and obviously that component has to be evaluated for failure. If the steering wheel is loose, there are only limited causes of that including wear in the steering linkages, such as the tie rod ends, or possibly faults elsewhere in the suspension which cause the steering knuckles to move (the part that holds the axle hub). In addition, in electro-mechanical steering systems, there is a possibility of faulty signals being input that affect the power assist and make the wheel move uncommanded or not in the manner expected based on the driver’s steering input. In any event, the steering system on your car is far from the most complex system and the parts count is quite limited. Thus, I share your bewilderment, and dismay, that the issue has just been already simply resolved. If you want a prompt resolution, which would commence with a diagnostic, just request a steering system inspection and the responding certified mechanic will get this diagnosed and finally resolved, right at your location. If you have further questions or concerns, do not hesitate to re-contact YourMechanic because we want you to make the most of your repair dollars and help you to get the best possible results.