I was referring to the problem pointed out by the original post. that is doable with a thinkpad.
as for replacing motherboards and CPU, it is still possible on Thinkpads. the older T440p let you change CPU in its socket. Other more limited thinkpads let you replace the motherboard with a new one fairly easily (identical model). as for replacing your mobo by a more recent one, I think only the Framework allows that for now.