The lens shading map is probably not the issue, it would have some effect on color but it wouldn’t be too significant.
I have been experimenting with a workaround that applies the GainMap to a dng file before editing, so that the editor doesn’t need to support GainMap. If you post the dng I can run it on that file and you can see if it looks any better than the original in Darktable. I would assume that Lightroom already has support for the GainMap.