Hi @Msaga.1 ,
I did not fully understand the question, but
if you have a value of 1 g on one axis and zero on the others for more samples in a row, your device is stationary.
in general, if the values of the accelerometers are stationary (they can change because of noise, but it is a very small change) the device is stationary.
to understand if you are moving, you need to check several samples in a row.
in the easiest case: if your signal is stable until sample in t0 and in sample t1 the value has changed by a not negligible amount, you know there was a movement (this is how the wake-up interrupt works, in a simplified way)
if I did not answer you properly, please, try to rephrase your question so that I can better understand it.
Niccolò