As it turned out, the problem is not in the plugin.
In some smartphones (in my case, Xiaomi Redmi Note 4), there is simply no hardware sensor with which this plugin works, namely Sensor.TYPE_STEP_COUNTER
You can view its availability by an application like https://play.google.com/store/apps/details?id=com.cpuid.cpu_z
In the absence of this sensor, the calculation of the number of steps is through interaction with the accelerometer, by analyzing and filtering data.
According to this principle, applications from Google Play are working, which can count the number of steps on my device.
What does the device have with a different type of sensor for counting the number of steps - Sensor.TYPE_SIGNIFICANT_MOTION
After consulting with a programmer on JAVA, testing with examples, and making sure that it works, I ordered a plug-in revision with the inclusion of support for both types of sensor and accelerometer there. Everything works in the same way as a native application from Google Play.