Have to grind / brute force for every part. I can't remember how long the mnemonic took to get one that yielded a c0ffee fingerprint, but it wasn't too bad. A 6-char hexadecimal match is over 16^6 possibilities so not too bad, but the bip39 calcs make each iteration slow. Probably did ~50 million over a few hours?

The 3Coffee address was the killer. Nested segwit addrs use base58 so a 6-char target is 58^6 possibilities. Had about 10 threads running for 2-3 days grinding address indices. About10.2 billion attempts.

(everything would've been probably 1000x faster if I did this in rust instead of python, but taking on rust would've been too ambitious)

Then the c0ffee txid was probably the easiest part. The end of the OP_RETURN has a random hexadecimal string; that causes the transaction to hash to a different txid each time. That only took about 2hrs of grinding while I made lunch today (an easy 4.4 million tries)!