I tried for decades to let go of the (completely justified) hatred I have for my parents and tried so hard to have a semi-normal relationship with them,or at least one of them.

Nope, didn't work, they are just horrible people nobody sane gets anything positive from being around. My husband pointed out that they were a huge negative in my life with no positives and why was I doing that to myself?

I let go and stopped contact with them and it's been one of the best things I've ever done for my overall well-being.