When you say you bricked the motherboard, are you sure the CPU, RAM, etc., are undamaged? If the two motherboards have similar chipsets, the change might not be enough for Windows to complain about a board swap.
Thinking back I've completed pre-installed Windows 7, 8 and 10 setup on laptops using a Local Account and I'm pretty sure they reactivated automatically when the OS was reinstalled. I much prefer local accounts and the ability to choose the primary account name myself, so I don't use my Microsoft Account when installing Windows.
I even managed to fool a brand new Windows 11 laptop into accepting a local account by switching off the WiFi Application Point half way through setup. The laptop was supposed to come with Windows 10 and I was confused and surprised when the Windows 11 desktop finally appeared. I wondered why setup looked slightly different. A quick wipe and reinstall of Windows 10 fixed it.