Okay
So eazy peazy:
Is the stick actually centered, and works correctly? Then it shouldn't have more than the default deadzone
If it not centered? Then its borked, and you need to RMA it.
I got a SN30 PRO 2nd revision, and the left stick lasted about 6 months before wearing apart and just drifting.
Once its borked, you can't fix it. Windows calibration tool isn't designed for complete recalibration to deal with silly deadzones due wear.
I had to RMA it, and I live in a reasonable country, so that was easy.
I am tempted to get another one, but I fear they use the same mechanic for the sticks, ergo it will die within half a year. The reason I might want another one is that the DPAD and buttons are tested and true designs, even if the parts are subpar and chinese.
And I was also displeased with the fact it did not have full rumble support, only light rumble. Input lag and sync could have been better, but bluetooth has always been kinda borked on Windows.