My brain has this great selective acceptance of canon vs non-canon fictional material. It's honestly automatic. I love it.

The epilogue of the last Harry Potter book (and Cursed Child, though I've never read/seen it): not canon.
That tumblr post where Harry becomes Defence Against the Dark Arts teacher: 100% canon.

Episodes 7, 8 and 9 of Star Wars? Not canon.
Rey, Finn, Poe, Kylo Ren existing as characters in that universe? Canon.
(Basically everything involving Luke Skywalker in episode 8 is totally canon btw)

It's seriously automatic bc I spent pretty much all of eps 7 and 9 watching the movies thinking, 'Yeah, but this isn't REALLY the story, is it? They'll make the real one later. This is just bad fanfic.'