The 16" MacBook Pro I bought is "managed and supervised"?

It's either stolen, or it wasn't properly removed from the MDM. Return it. The company managing the device can push out, or add or remove software, and could certainly wipe your entire device at any time.

My MBP is managed and supervised by me. It will be that way until a new manager/supervisor repays my original investment.

Unless the manager/supervisor took out firmware-level locks, completely restore the MacOS using "internet restore" ... downloads the MacOS from the internet ... to what the Mac thinks it should be, then it will be yours completely: https://support.apple.com/en-us/HT204904

If you cannot, then there are firmware-level locks you cannot remove yourself and you need to get your money back.

Hi number11plus,

Unfortunately, the Mac you bought is registered in Apple Business Manager as belonging to Atomic Talent Canada Inc.

When a Mac runs the Setup Assistant, it contacts Apple servers to check if its serial number is registered with a business:

• If the serial number isn't registered, setup continues as normal.

• If the serial number is registered in Apple Business Manager, Apple instructs the Mac to join the mobile device management (MDM) server specified by the business that registered the Mac. At this point, the Mac displays the Remote Management screen, and the Mac becomes managed by the business's MDM server.

To resolve this issue, please contact the company in question and ask if the Mac was lost or stolen. If it was legitimately sold or given away by them, ask them to remove the Mac from Apple Business Manager. Then, erase the Mac and ensure that it doesn't prompt for Remote Management.

You need to return the device:

Apple Platform Deployment - Apple Support

Well, guess I underestimated the power of the manager/supervisor to reach the device, forever.

I bow to the greater knowledge.