“quickly” is a matter of discussion but https://github.com/j0be/PowerDeleteSuite is pretty effective. You can set it to do an edit before you delete (which may or may not prevent mods from seeing what you posted… it is questionable) and it doesn’t need any other scripts. Just start it up and leave that tab open for a few minutes/hours.

That said, reddit restored the content of most people who deleted their profiles during the API protests. Allegedly that was a side effect of reverting state to restore private boards and remove all the John Oliver hentai but… yeah. For what its worth, I re-ran on my accounts and they are still deleted as of a week or so later.