The price exceeds the motherboard cost so no one fixes motherboard.

But you did reveal something good in your post. The MAC ADDRESS is the issue. The smaller chip that holds the MAC address would not be a hard to replace. But finding the equipment and person skilled to do the work is the issue. If this is worth doing I'd expect the bill to be in the thousand buck range.

Then again I'm surprised no one told you can change the MAC address. among other methods.

So yes there are options here.