Which acceleration axis are you reading? Or are you reading the 3 dimensional acceleration module?
Consider that the LIS2DW12 accelerometer is 3 axial device, and in a rest condition with Z axis pointing to the ceiling and X and Y on the plane, the output will be about 1g (1000mg) for the Z axis that is measuring the Earth gravity acceleration, and about 0mg for both X and Y axes.
In case you are reading the total acceleration module, the results will be similar, since it is just the vectoral sum of the 3 above mentioned components.
If my reply answered your question, please click on Select as Best at the bottom of this post. This will help other users with the same issue to find the answer faster.