I don't know from Darktable because believe it or not, I basically never use it.

(I am of the opinion that obsessive insistence on RAW development boils down to hipster posing, only because "everyone knows" that Real Pros Only Edit RAW. Bullshit. You are holding in your hands a $2200 piece of photography equipment designed by extremely serious and very talented engineers that's jam packed with dedicated, purpose-built image processing chips specifically tuned to work in concert with the hardware in your camera and output final images already processed for you, all of the above backed by decades of experience. But no, some dweeb on Youtube tells you he knows better. Rant concludes.)

Anyway, what I did was take Corel PhotoPaint's white point tool and stab approximately here:

Then I turned brightness down -10, and contrast up +5, based purely on speculation:

Then I punched vibrance up +5, and decided that looks pretty good:

Then I negative masked the background with the "magic wand" (i.e. color similarity) mask tool. There were also a couple of crumbs around the foot in the lower right I had to mask off by hand:

Feather the mask by a wide radius (I used 300px) so that knocking out the background will not leave any harsh edges:

Then invert the mask and delete it, whilst your background color is set to pure white:

Et voila. These are heavily downscaled. You get the idea.

The reason for using a negative mask (i.e. you mask off as if to exclude the subject, then feather, then invert) is so that the edges of the image don't also become mask edges, which results in a highly amateur looking and distinctive square vignette around the corners, which you then then have to airbrush out. Fuck all that noise; do your mask backwards, then invert it. I learned this the hard way, many years ago.

You could probably do the same in GIMP, if you were committed to figuring out just where the hell it hides all the requisite tools, or which of them inexplicably require an external plugin. I already have a Corel license due to work. Therefore, the hell with it.

Apropos of nothing, just now I tried playing around with Darktable's white point tool (located in, apparently, the rgb levels module). I can't tell if it's busted, or if it just doesn't work the way I expect it to. Part of this is no doubt due to the mantra that "Darktable is not a creative tool," but is instead intended for correction. It's not an image editor. But we are significantly altering the aesthetic of an image for artistic purposes; that's creativity. Not to mention the inevitable removal of dust, fingerprints, blemishes on your backdrop surface, etc. At least that's what I always wind up having to do, which means you need to fire up a real image editor anyway.

You can achieve similar results in Darktable by messing around with the exposure slider located, appropriately enough, in the exposure module while optimally keeping the overexposure warning (press O on your keyboard) enabled. But this is imprecise and annoying, and difficult to make consistent. Not to worry; someone will surely come along in a moment to tell me I'm wrong, and point out the correct six or seven ways an individual might accomplish half of this, along with the nine or ten ways they'll have to do the other half.

Darktable is also, if you ask me, the sibling poster child to everything wrong with open source UI design right there alongside GIMP. Why for the love of all that is holy, for instance, are so many things expressed in numeric values that you can't type in, and only manipulate via sliders? Why is the reset button so hard to find? I could go on forever. The world would be a better place if people could see their way clear to not parroting to newcomers that they absolutely "must" shoot RAW and use Darktable when all they really wanted to do was take acceptable pictures of their models or knives or whatever.