Update October 19, 2021 = A DELL-Cares agent setup service.
I have exactly the same problem with the touchpad. It is barely responsive. I have to resort to the external mouse. Reinstall the Windows 10 system, still not working. In the Device Manager, the Dell touchpad does not show up, only the HID compliant mouse appears there.
m15 R4, touchpad not working, #2