When I first got my Mac it was easy use and I could get into it only twice. Then I tried to get into it at work and the encryption password was still in someone else’s account. I made an appointment with the Genius Bar at Apple and they had to erase the whole thing install Big Sur iOS and restart the whole MacBook. Mind you it didn’t cost me anything but it was the inconvenience of not being able to use it out of the box, driving out of the way, and appointment wait, and the major thing was they had it for two extra days on top of me having to provide them with some sort of receipt or purchase number to make sure it was not shady. I gotcha that it is all security stuff and making sure that nothing funny happens but test your refurbed products and send something with the serial number on it saying it the product has been cleared and this serial number is now the purchaser  MacBook.