Hi!
Yes there is a way to fix it without replacing the motherboard.
First you need to get the motherboard out, then you will notice that there is a "Conductive pad" for the A,B,X,Y buttons located on the motherboard. Replace that one for a new one and you are good to go!
While you are there, it's recommended to replace the rubbers as well!
Guide: [guide|25399] (in Step 22 you see the conductive pad already).
Part: https://www.aliexpress.us/item/2251832296403090.html?gatewayAdapt=glo2usa4itemAdapt
If you need anything else, please let us know!