I don't know man... If that oak tree would make you try to be a better person every day and give you comfort moving forward in life, I don't see a problem tbh.
The truth is we know nothing of the life itself and probably never will. You can try to replace beliefs with science, but at some point, everything comes down to some number that is just a constant that no one can explain why it is of such a value, the more you dig the more you know that we just know nothing.
You can call religious people stupid if that makes you feel smarter, just remember that a lot of great scientists were religious as well (Newton, Euler, Pascal, etc.). Noone can change your mind but you.
As for the books (dk which you're referring to but I guess Bible), a lot of the characters were historical figures, mentioned by historians. Sure it was unfortunately redacted a lot, probably due to changing moral standards that would be not acceptable anymore, but the main message stays the same - be a good person.