I just generated this new account using eschanostr, using the following command: eschanostr -r "tests"

So, check my npub, it stats with npub1tests[...]
nostr:note1n5qzt7xkp3re6gsfvat566anf7w699rf3gttzzqq6e9vruv3jwtq99z8f0  

 https://image.nostr.build/d0af8054a138f5ea4704402218b0bdc9f5dce96d5d62cfb830b6851a29dd8bdb.png
nostr:note1nzvwr5ef4rqf3ksft63kw52qrva24827usz7qzpkf7mdv7ttle6s2zhtkk  

 https://github.com/mleku/realy/tree/dev/cmd/vainstr

one i made... it's very fast because it uses the bitcoin core secp256k1 signer library for deriving the pubkey 

 it can make a key with 5 letters at the end like mine now in about 10 minutes, iirc