I was in the begining so sad to find out that the shater of my Sony a7III was controled by an optic cable , and Not usb.
But most important the stabiliser is not smooth at all when Paning , even on a tripod trying to pan with the aplication on my iphone
or sticks .... it hopps speeds for a 2 -3 seconds then it becomes stable. I tryed evrything calibration recentering auto tune balance test system calibration .. evrything looks normal
i am using the kit lens 28-70 the setup is so light .... and still paning is really horible ....  heeelppp

Unluckily same here. Panning can be smooth at some times, but speed jumps quite often and smooth panning is impossible.
Hope DJI finds an improvement in their software!

Have you tried changing the "Smooth Track" settings. I was able to get some "smoother" panning by slowing things down a bit. I slowed the pan down to 10. With that said... the Ronin S is not as smooth as my slider.

I am not sure if this will help or not but with the Zhiyun Crane, there was a setting that had to do with telling the gimbal the weight of the camera. Not literally, but it was a small, medium, large kind of thing. Since the Ronin-S can handle a wide range of camera weights, I am wondering if there is an equivalent setting. I am still waiting on mine.

The weight of the camera is automatically calculated and considered by the Auto Tune function, so no need to tell the gimbal the cameras weight.
I also played with the SmoothTrack parameters but the more you lower the pan´s speed factor the greater the control error becomes, means the offset to the angle where you hold the grip to so you have to oversteer a lot what I don´t like, especially not when following pan and tilt!
Again, "wrong" PT1 behaviour is the problem "I" see (...as an electrical engineer), but I may be wrong with this.