There is no such thing as locking wrist and unlocking. Continue to adjust the the grip angle, style, and strength as you work on the technique and swing path. With that in mind, you have to calm down your feet meaning no jumping. At your level both your feet should never leave the ground. Try placing more weight toward the heel as you step and the heel toe weight transfer should be solid with no rushing or hesitation.
To get the feel of the correct swing path is not a simple thing but you need to keep working on to refine. Roughly your right shoulder should feel like pulling out a heavy sword from your waist. But, bend your elbow and tuck the elbow toward your chest. As the shoulder pulls as in pulling out the sword, your elbow, hand, and racquet should swing out to the contact point. Regarding the opening up the shoulder, it should happen only well after the contact and most of the supination (arm twisting clockwise) happens. Not during the contact as you tend to do often.