And for your ship to become canon, it needs to have a narrative supporting it and backing it up, which it doesn't. You cannot show me a single scene with romantic subtext from an authorial point of view. It's alright if you admit your fantasies to be fanon yk
If you actually believe changing who Katara ended up with would somehow fix her writing, then your issue isn’t actually with her character.
Your issue is that your ship wasn’t canon.