I wasn’t able to disable Copilot in Office without threatening to cancel via my account management page. It’s only then that they give you the option to fall back to the originally priced plan that specifically doesn’t include Copilot. And even after that, Copilot apparently won’t be removed from my locally installed copies of the Office apps until my plan renewal date in April! I’m pretty sure I’m gonna use the time to transition all my documents to LibreOffice and fully cancel my MS Office plan before it renews.