If you have the VNC password and it looks encrypted (a few bytes, like if it could be and encrypted password). It is probably ciphered with 3des. You can get the clear text password using https://github.com/jeroennijhof/vncpwd
vncpwd <vnc password file>
You can do this because the password used inside 3des to encrypt the plain-text VNC passwords was reversed years ago.
For Windows you can also use this tool: https://www.raymond.cc/blog/download/did/232/
I save the tool here also for ease of access: