Every time people talk about putting billionaires to the guillotine I'm thinking "in this scenario where you can execute the richest people on the planet you can clearly do whatever you want, so just take their money"
I personally think it would be way funnier to stick Bezos and Musk and them in bland middle class lives like Ray Liotta at the end of Goodfellas, it's a perfectly good life if you aren't accustomed to being able to buy entire political parties or go to space or command a herd of creepy little followers who would probably literally kill for you
Want these chumps to suffer? Make them unimportant.
I want billionaires to live a basically comfortable life in a society where no-one, including them, has to worry about food, shelter, healthcare, or transport. I bet that would be miserable for them.
Yup! They would look around and see ordinary people living nice stable lives with their basic needs taken care of, and they would know this was all done with their money but without their input, and they would haaaaaaate it.