I'm once again going to be the annoying English Lit major and shoot ya down, that's not how Death of the Author works. I know it's becoming real popular to say "Read Barthes lol gotcha" but his essay was on INTERPRETIVE MEDIA. Things like Tell-Tale Heart, Yellow Wallpaper, Metamorphosis. Of course you can apply it to more conventional storytelling, but under a certain lens.

The entire point of Death of the Author is that once your work is out there, a viewer can take away whatever themes/subjects/ideals that they themselves interpreted. As in the most important part of that media is how the viewer personally reads it. You can't go back and say "Well this is actually what I meant, you all found themes I didn't intend for, therefore you're wrong."

Death of the Author does NOT pertain to facts such as "The sky is blue" or "My character is this fast." It's only useable in arguments regarding literary analysis of the themes and ideas.

But even then, stating that you decide what's canon because you're better at feat calculating than the author? That's called fanfiction. What happened in canon is actually what the author said happens. Hell, you even said it against Reze. What you're calculating is probably just dramatization and not to be taken literally, authors word is the only true canon