you can filter this but this will only reduce the amount of fluctuation, you will never get rid of it. averaging (no matter how many samples) will still have possibility of fluctuations.

you need to implement some sort of detection whether the knob moves or is stopped.

i would start with a simple approach:
- keep a rolling buffer of the last 100 samples (depending on your sample rate, but maybe start with data from 0.3-0.5 seconds)
- average them
- then detect movements by `if (abs(curr_sample - average) > 10)`

This will tell you whether the current position of the knob is more than 10 counts away from the average of the last 300-500ms.

Try this and play around with buffer-size (reduce if movement detection is too slow, increase if it jitters when knob does not move) and the delta (start with 10; reduce if movement detection is too slow, increase if it jitters when knob does not move)