Forgot to remove Find My from a Macbook that I sold, then simply couldn’t erase and remove it remotely: it would come back every time the buyer tried to get in again.
In the end I was tossing up a full refund, or giving them my Apple password. Settled on the latter, with a new password generated and my finger hovering over the save button as I read out my old password. Not sure I’d recommend that approach, but at least they were happy. And I have a new password for the first time since 2015.