I have crazy idea to produce mnemonic rules for every DID, maybe fancy-AI tech would help

Too much entropy. Any 128bit+ thingy with global uniqueness, whether it’s a hash or guid or public key, doesn’t matter. It’s not ever going to be memorizable for mortals.

You can generate novelty nonces for the first X chars, but you will eventually get mumbo jumbo, at which point it’s never gonna be a “good name”.