SHA256(privateKey + "some secret value")
Truly, this turned out to be an incredibly straightforward process;Lol:D I realize that I was needlessly complicating things. That's the true advantage of sharing whatever thoughts occupy your mind—people make it more easier.

Thanks
I receive numerous messages in my inbox from individuals who are diligently attempting to solve Puzzle 66 and choose to share their ideas with me. However, I've noticed that not a single post from them exists within the community. I would advise them to come here and share their ideas; doing so will undoubtedly be beneficial for them.