I know this isn't a proper solution, but in the meantime I've been using the following redirect rule to change minecraft.fandom.com links to the corresponding minecraft.wiki link:
^https://minecraft.fandom.com/wiki/(.*)|https://minecraft.wiki/w/$1
You can use this by going to the Kagi settings page, clicking on "Advanced", then clicking on the "Open Redirects" button, and clicking on "Add Rule".
