Cannot remove device from Apple ID

My MacBook Pro 2017 had a non-functioning screen. When I took it into the Apple store for repair I found this uneconomic so came home with it and a new MacBook Pro. I have taken the old one to a local computer shop to wipe the hard drive before it is recycled as it will need to be plugged in to another screen. I was told to remove it from my Apple ID. I have done this before after replacing an iPhone, but have not been successful with the MacBook. Checking the devices on System Preferences>Apple ID shows it, and that Find My is turned on. I cannot see how to turn it off remotely. Clicking on it in the sidebar and then "Remove from account" removes it on the page but not from the sidebar. When I sign in next day it is back and has not been removed at all. I tried signing in at iCloud.com. There the two MacBooks have been reversed. It is the 2017 version (last 4 digits of serial number) that shows an ikon with Monterey while the one bought this month has an ikon showing the Catalina desktop. I have done nothing so as not to remove the wrong one. I have two factor authentication for Apple ID but have not had a verification code. Has it has been sent to the non-functioning MacBook? I have found nothing on the support pages or discussions that helps. What do I try next? I suppose I could just leave it in the list of devices even if it has been recycled for parts but would rather not.