> Anything you tumble, you can (provably) de-tumble.

Source? Enough CoinJoins (Wasabi+Joinmarket) and I don’t think so. Note CJ work a bit different than the oldschool custodial tumblers. Combining CJs with LN (reverse) submarine swap for another layer.

With large enough anyonymity sets you should have plausible deniability. This is also a bit time-consuming, more so the larger the amount; there’s no way to do a complete end-to-end transaction of billions of dollars untracably in mere hours without standing out I think. But if you have days/weeks to break the link I think it’s def doable and done.

Obviously make one single mistake and you’re out, but that’s in the nature of these things.

If I’m wrong I’d very much appreciate something substantial.