That was a very good discussion of dark counts and how to get rid of them. One other way that astronomers remove dark counts is to cool their cameras, either with electronic coolers or liquid nitrogen. Once the sensor temperature drops below about -10 or -15 C, the dark counts become pretty much negligible, at least with modern sensors. Not a practical solution for a non-specialized camera, of course. There is one source of noise you get with long exposures that you simply cannot get rid of any way but manually (including writing a program to find and delete the artifacts). That is cosmic rays. If you have your sensor on for any amount of time longer than 30 or 60 seconds you will probably have cosmic ray hits. These are from muons produced by collisions of high energy particles in the upper atmosphere. Some of the "hot pixels" you see in your images are these cosmic rays, and no dark correction will remove them. I wanted to add this bit so that people do not get frustrated if they see artifacts that the cannot remove with the method you described. Sensors also have innately hot (and cool) pixels, too. These are pixels that are intrinsically more or less light sensitive than the pixels around them, and they give bright and dark spots that cannot be removed by a dark correction and that are not temperature dependent. But that is a whole other topic, and for all I know, consumer cameras have processing built into them to minimize the effects of these pixels.
I knew all this but you have done, again, a great job of explaining things. Love these 'ask' vids. Short and easy to watch. Keep 'em coming. Like the Adorama vids.
Paul Reiffer also did a live video today on night sky adjustments.. He noted that in Capture One Pro, you can use the single pixel slider to fix the heat noise. It's pretty slick.
