Hi!
Stick drift can only be repaired by replacing it!
Note, that you do need soldering skills to replace it, it won't be easy.
While you are there, I recommend to replace them for Hall-Effect joysticks straight away when one of them is defective.
Guide: [guide|142488|DualSense Joystick Replacement - iFixit Repair Guide|new_window=true]
If you need any more information, please let us know!