btcrecover, which I mentioned above, does support GPU-accelerated password searches for wallet.dat files (or for dumpwallet.py files like you also partially posted above).

It's still pretty unclear (to me anyways) if this is a password you remember most of, or if it's a KeePass or similar password which you don't have any of. If it's the latter, and if it's a complex as you've stated, than there's absolutely zero chance you'll ever be able to recover it without recovering it from KeePass.

Here's a link to the time it would take to brute-force a random 30-character long password (upper + lower + digits) using 4 high-end GPUs.