If you don't like the choices a writer/content creator makes for a character, you're not obligated to hate the character. And although you can't argue that it isn't 'canon,' you don't have to only see the character through the lens of the bad thing you don't like. If you think the writer/content creator didn't make a character change or character arc convincing, you don't have to pretend that it was believable, and base your perception of the character off of something you thought was badly done or hard to believe.
I'm gonna give an example from the Office. The character of Andy Bernard started out as a meant-to-be douchey, meant-to-be annoying character, and then went to anger management and when he came back started being portrayed as more likeable, though still very flawed. This continued on for seasons, but then in the last season (though arguably starting with the season eight episode 'Welcome Party') Andy started being written as a bad boss early Michael Scott style who his coworkers didn't like. I did not like that direction, thought it was unnecessary despite some funny moments and good plot points coming from it, it sometimes wasn't done very well, and I felt like it was a mistake. I'm not obligated to hate Andy because of the choices the writers made, and I can say 'this felt out of character and it was a bad choice that I think shouldn't have happened,' and other people getting mad at me for not seeing Andy exclusively through the lens of who he was in season nine would be ridiculous. If I made some kind of statement like 'Andy was a pretty good boss at the start of season eight' and someone was like "yeah well he was horrible in the ninth season so he was clearly just pretending to be a good boss" it'd be ridiculous. And if I said 'I just skip over a lot of season nine Andy so I can enjoy his character more,' and someone responded with 'I can't believe you like a character who did such bad things, clearly you're an idiot,' it'd be ridiculous.
Why do people have this idea that if the writers decide something for a character (no matter how late in the game) you have to base whether you like or dislike a character on that alone? If you think something is badly written, if you think that something is a bad choice, if you like a character that's a villain and want to write them as a hero instead, you should be freaking allowed to just clip clip cut out the things you don't like.
I like the character of James Ironwood prior to shooting Oscar, I don't have to say 'well the writers decided he was a completely evil irredeemable villain and therefore it wouldn't be moral of me to like him and now when I watch the Fall of Beacon in volume three I'm morally obligated to seethe about what a bad person he is, better never write fanfics where he's a good guy ever again!' ¯\_(ツ)_/¯
I've written fanfictions where I have certain characters just be better than they were in the universe because that makes me enjoy the universe more. I've written fics where characters who do bad things that the writers treat as acceptable apologize for their actions. I've looked at characters who have never been anything but villains and then written fics where they're just flawed good guys because I wanted to explore that universe and loved the character concepts. I've disliked whole movies in a series and decided 'in my mind the franchise cuts off here.' There's some pieces of media where I have to adjust everyone in order to enjoy writing for them, but I still enjoy the characters. I've loved badly written characters since I was a kid despite thinking the writer choices were off, and put Pixie Hollow Disney fairy books on my Christmas wish-lists even though my dad reminded me Tinkerbell tried to murder somebody because I could just ignore that. The very first thing I ever wrote was a Star Wars fanfiction when I was six and I didn't like that George Lucas made C-3PO a scaredy cat so I made him into a brave hero instead. I'm not going to just base what I like or don't like on whatever thing the writers wanted or intended. Why would I have to do that?
And honestly, I'm not posting this because I have a real problem with people who do throw out characters when the writers want them to, or only portray or see characters how the writers want them to, or anything like that. But for the love of God I would like them to stop getting angry or judgey when other people are just like 'huh, I don't like this change. I reject it for my own headcanons. This isn't how I see the character.' Like... Why the hell does it matter so much to other people that we must only see fictional characters the exact way the writers intended and therefore must hate the characters who the writers make do bad things. Also this always comes with hypocrisy, because the people that try to police who other people are allowed to like always like other flawed characters or even villains lol, and always adjust their favorites to be better or ignore the mistakes of their favorites.