I would not be so quick to assume what is and is not ‘canon’ when the entire purpose of the writing for the game is meant to be how you prefer and interpret these characters to see one another. They are rivals, yes, but their relationship— every relationship in the story is not one-dimensional and goes beyond surface assumptions. You are welcome to have your own interpretations, preferences and ways that you ship yourself with the characters! But making assumptions about what is ‘canon’, especially in order to put down or be impolite to people who do enjoy that interpretation, is not a healthy way to interact with it.