Good luck if you decide to go forward with it. Just be extremely careful and understand what you may be getting into here and the risks.

It can be extremely challenging diagnosing these newer Macs even when you know their history. Keep in mind you will be putting lots of money into a part which has a completely unknown history. I also highly recommend checking the health of the integrated SSD to make sure it is not worn out (we actually had a worn out SSD on a Logic Board that Apple had replaced - the SSD did fail, luckily while still under the part/repair warranty). Plus the USB-C circuitry on these Apple Logic Boards can sometimes be half bad so you may not know you have a bad board until it is too late (power & data are different so one may work while the other may have issues). You definitely want to make sure to check whether a firmware lock is enabled or whether the Logic Board/computer is still being managed by a previous owner since there would be no way for you to disable either one. You have to be extremely careful when purchasing a used Apple Logic Board or Apple computer. These laptops don't behave the same way as the older Macs. Replacing a logic board is usually a final effort since it essentially is the computer. I have seen these laptops take forever to boot if I disconnect the Trackpad cable or battery from the Logic Board. The logic board is Apples term for the motherboard. How do you know the Logic Board is bad? If these USB-C Apple laptops have any sort of power or sensor issue, then the laptop can run extremely slow.

Macbook pro 13 logic board