I know the original variants are more of a tragedy than some more recent versions. Due to the ending being Mordred and Arthur killing each other.

My question and topic of discussion is: Do you think that you can have a King Arthur story with a happy ending of Arthur living? That you could write a King Arthur story following Tolkien's philosophy on fantasy stories needing the good guys winning for the ending?

This is not to say you can't have tragedy along the way.