“Is the surgery for receding gums successful?”

Usually the results can be from 50 to 85% successful

There are many variables to determine how successful. But most of the time
you will see Significant improvement

This is a tough one because recession can be a result of many different conditions. More often the heavy forces of clenching / grinding result in recession and the success of surgery is supported by clenching management (appliance therapy / splint use / Night Guard use etc.)
A misaligned tooth getting traumatized might need orthodontic alignment as part of surgical tissue care. Overall periodontal surgery for recession has never been more successful!