I don’t know about others, but I don’t think anybody deserves to die necessarily. It is faaaaar too merciful a fate for horrible people. I believe the worst of humanity - rapists, murderers, child abusers, etc. - deserve to live long, painful, oh so horrible lives.
My choice would be to put them inside of a 3 meter cube of steel, welded shut, with only a hamster bottle for water, a hole in the bottom for waste, and a nutrient paste dispensing chute. When the prisoner eventually dies, it is bury the whole thing out in the desert to be their unmarked tomb.
I’d go hunt down Ronald Regan at about age 30 and empty an entire magazine of .45s into his dome while he slept.