Clean around the analog stick with compressed air
Rotate the stick while blowing air into the base
Use a small amount of isopropyl alcohol on a cotton swab around the stick base
Move the stick in all directions while cleaning
Reset the controller using the small reset button on the back
Reconnect the controller to the PS5 with a USB cable
Update the controller firmware through PS5 settings
Adjust the deadzone settings in supported games
Test the controller on another game or console
Replace the analog stick module if the drift continues
Contact PlayStation Support if the controller is under warranty