With MacOS, there's something called the DFU Firmware Revive/Restore, which is a deep recovery process for unresponsive Macs. To run a DFU Revive/Restore, you have to have another Mac to update or ...
Apple has updated its website with changes to the checkout flow when buying a new Mac. Previously, the Apple Online Store would show you a range of preconfigured options with specific processors, RAM, ...