If they really want to get her out of the Veep job, they have a hundred other nasty options to oust her without rewarding her for sucking at the job.
They're going to try to find a relatively normal hardcore leftist black woman to minimize the backlash from announcing the color and gender of the nominee before selecting her. Ketanji Brown Jackson, leftie judge from California.
Harris has some leverage and some power here. Yes, she could have an accident or be despondent, but how often do they want to play that card? Moving her to the Court doesn’t cost much and solves a big problem.