i wrote a 24 word code some time back. nobody cared then. it only had 7 bits of check byte on it, 25 words gives you 18, but i figure 7 bits is probably enough to catch most obvious typos.

the thing is that seed phrases used with bitcoin do not let you convert an existing one to it. that's what my design solved, it was not a seed to generate a hash like is common with 12 words. if you vanity mine an npub you don't have that option, at least, the chances of finding words in the bech32 from such a hash-generated secret deriving the pubkey is a lot smaller field compared to a verbatim encoding like my 24 (or 25) word encoding.

Correct, NIP44 encryption. Can only be decoded with your nsec.

Unfortunately we can’t go back and fix Nostr private keys.