Why don’t we just inject them with a massive amount of street heroin?
Chase the dragon to eternity...
I suggest injecting them with a Fauci Flu vaccine, then with “boosters” until they die ... which shouldn’t take too long. Although an added benefit of this highly effective method of execution would deplete the massive inventory of this potentially lethal material, some empty-headed judge would probably dismiss it as “cruel and (certainly) unusual punishment” ... a rationale that would have medical “experts” in a bit of a quandry.