Microsoft cannot assist with UEFI passwords. If part of a business, check with your IT administrator. For a personal device: The only real option is an out of warranty exchange for a refurbished device. You should go to account.microsoft.com/devices and select a device and start a service order. If your device isn't listed, select Register device to add it to your account.
They don't list full replacement cost, and the Surface Laptop 3 is past end of lifecycle, which may mean there are no full replacements available.