I have found inspiration for my own writing in myths. I am an old movie fan and was watching Jason and the Argonauts (1963). The portrayal of Hercules in that movie intrigued me. When I read the myths about Hercules, I realized the screenwriter had done a good job of sticking to the myths when developing the screen character.
Hercules in the myths is not very bright, intensely loyal to his friends, has a mean streak, and a tragic past. For a minor character I created, I deleted the mean streak and made him a huge man, not smart, very kind, and with a tragic past.
I have also created two other minor characters who are identical twins. In my work, they are middle-aged men and go by the nicknames Sunny and Set. Even though they are identical, they have opposite personalities, Sunny living up to his optimistic nickname, and Set living as a criminal. It was after I had developed these characters that I noticed how much they resemble ancient Egyptian mythology.
Osiris, who is sometimes claimed to be the son of the sun god, is good and his evil brother Set kills him. So I could write the story with my character Set acting like the mythologoical one. Or I could turn the myth on its head and have my Set save or protect his brother. One thing I like about myths is that I don’t have to follow them precisely. Once inspired, I can use them any way I want.
Myths aren’t like copyrighted books. Even in ancient times, there might be several versions of one particular story. There are not a lot of sources for the Norse myths. But even the few that exist don’t always tell the same story the same way.
I can change the ending of a myth to a happy one. I can put a female character into a situation that originated with a male one. That would change the storytelling completely. In fact, once I get through with my story, it might be hard to find the myth. But it was still responsible for kicking off my creative spark. So I keep revisiting myths because I enjoy reading them and because I never know what inspiration might spring to life.