Why getting same output from fir filter even after changing the cutoff frequency for acceleration time series data?

Hello everyone. Hope you all are doing well. i have question about filtering.

Currently i am working on pedestrian step detection using inertial measuring unit (accelerometer/acceleration data), i need to do filtraton of my signal at preprocessing level. could anyone suggest which one will be the best filtration algorithm to get good accuracy.

for now i used digital lowpass fir filter with order=2, window size=1.2sec,sampling frequecy=200hz but seems not working. i want to use a lower cutoff frequency. i used 0.03hz and 3hz of cutoff frequecny but i am getting the same result for both frequencies. i need your guidance or help that how can i proceed. below i am attaching the filtration result and code at 0.03 and 3hz.

could some sone suggest me or provide any good filtration and how can i work on that. Thanks

Fs = 200;

Hd = designfilt('lowpassfir','FilterOrder',2,'CutoffFrequency',0.03, ...

'DesignMethod','window','Window',{@kaiser,1.2},'SampleRate',Fs);

y1 = filter(Hd,norm);

plot(IMU_ULISS.time(:),norm,IMU_ULISS.time(:), y1);

title(['low pass fir filter']);

legend('norm', 'Data filtered')

xlabel('Time (sec)');

ylabel('Angular Velocity (rad/s)');

at 3hz

at 0.03hz