@jerry My recipe for data detox: Have a encryption root in zfs break while you deleted the old backup, because you are in the process of rearranging your storage pools.
It's quite fast. First you wonder: "Why won't this decrypt?" You double-check the key. You confirm that the key was all right. You realize a big chunk of stuff is just gone into crypto nirvana. You start to wonder what was lost. You spiral into panic. You realize it won't help. Be at peace.