I’m not quite sure what you mean here - presumably the same kind of data/analyses that would get you a dissertation and journal articles are the kinds of data that would get your adviser grants. They’re not necessarily mutually exclusive categories of work, you know what I mean? Besides, stiffing an advisor could lead to getting kicked out of the lab or “coached” out of the PhD program. You really don’t want to tee off your advisor, at least not until you’re finished.
I think that one shouldn’t go into a PhD program planning to drop to part-time after quals, because that’s a really good way to be stuck in a PhD program for 8-10+ years. But I HAVE seen students successfully work a full-time job during the dissertation phase if the full time job contributed to the dissertation. So that meant that 1) the dissertation data was being drawn from work that was being done at the full time job, and 2) the person’s supervisor at the full-time job was fully on-board with the person getting a dissertation done on company time. Others can chime in, but writing a dissertation for me at least was in and of itself a full-time (and exhausting) job - when I was in the deep writing phase I was routinely writing all day from 10 am-6 pm and sometimes doing a little more writing in the evening after dinner. I did work a part-time job that was about 10 hours a week when I was writing, and I can’t imagine doing more unless it was directly related to my dissertation work. This is especially because if you are serious about an academic career, you might still have one or two side projects going on while writing your dissertation (I did; they eventually turned into papers).