Unfortunately, what you want to do is not going to be possible unless you get very, very lucky.
Bafang mid drives do have such a settings interface hiding inside of them, accessible via a special cable and the right software (The Speeed app in particular, three e's in the name; I didn't mistype). That programming cable you ordered is for that purpose. You won't get any use out of it with a hub motor. Thats because the Bafang mid drives have a controller built inside of them, and your access to their internals reaches out to the settings interface in that controller.
Bafang hub motors do not have an internal controller. They have whatever controller you hooked up to. This one is yours I suspect:
The Sondors bikes of more recent vintage have a settings screen in the display that lets you adjust the assist power percentages of each PAS level. But... they are tied to a manufacturer-specific display that is mated specifically to that controller. you have a DPC-18. The only way there is anything to edit is if you find something in the settings section, that you got directions to in the vids above. If your DPC-18 does that, its part of a special order batch (which do exist, but I would not bet the farm on such a thing).
Chances are to get what you want you are going to have to throw out everything but the motor and get a controller that is not such a poor performer. A KT controller in particular, mated to one of their branded displays that has a fairly robust settings interface. Those controllers do not present PAS as an on/off switch, and I am certain you would be a lot happier with the assist levels. My Level 1 is around 80w of output which is pretty gentle. Unfortunately, if you change the controller you likely have to change the throttle and PAS sensor since the plugs are unlikely to match.