If you have the wallet.dat file, then use a script from the John The Ripper repo. Look for the file bitcoin2john.py.
https://github.com/openwall/john/blob/bleeding-jumbo/run/bitcoin2john.py

Generate the hash for hashcat by typing:
python bitcoin2john.py wallet.dat > myhash.txt

The output hash can be used to find the password using various techniques and the hash mode 11300.

More about Hashcat and different attacks check their webpage.
https://hashcat.net/wiki/

eg, brute force a 6 character password:
hashcat.exe --status -O -a3 -m11300 myhash.txt ?a?a?a?a?a?a

You need a GPU and a lot of luck and/or patience.