step count for people with disabilities

Is there a way to change how steps are detected on Garmin devices? I know some trackers detect footfalls while others detect arm movements. I have cerebral palsy, and the only arm I can use my Venu on is my disabled (right) arm. It is stiff and doesn't swing freely.

My average step count is around 1000, including long walks ~ 1-3 miles. I did a test and counted my steps to 300. This is on the sidewalk at a normal gate with walking shoes. Over 5 trials the Venu 3 recorded:

11 steps
15 steps
25 steps
10 steps
30 steps, or about 6% of my real counted steps.

I've done a similar test on a Fitbit device, which was about 85% accurate. I've followed the Garmin article for improving step accuracy https://support.garmin.com/en-US/?faq=z1TfJCqajl8ZEZey72gg98. I also turned off "Smart" data recording for recording by second. The above are using 1-second recording.