Chosen Solution

Since Apple has not changed the design of its laptops since I bought mine in 2016.Could I switch out the entire logic board to one that has a better CPU better GPU and more storage? Would it be possible? Would there be any side effects?

Given the heavy integration RAM & storage and the issues with the older keyboard. I think it would be just cheaper and smarter just to sell your current system and just get a new one. Don’t forget if you did this Apple would void your extended warranty on the keyboard and the logic board would loose any warranty.