Ahh, the wonderful world of troubleshooting! I would first check the micro controller. Unplug all the matrix wires from it. Plug it n and use a paperclip or metal tweezers to short each of the i/o pins assigned to the matrix (rows to columns) to generate key presses. If it generates all the proper key presses, then it’s not the controller. If some are missing, then try again to rule out user error, is still no go, then it’s either the controller is bad, or your firmware is bad. Check to see the firmware looks good to rule out which. Next check your diodes, makes sure they are all oriented in the same direction. If not, then it time to de-solder and fix. You can also check to see if there are any broken solder joints in your wiring, fixing any that look broken. If they are then you can carefully reattach your wires, double checking that you’re putting therm where they’re supposed to go. Then plug in and use the tweezer method on the hotswap sockets. If that works, then test the keys, sometimes the pins on the switches bend, instead of going into the socket. Pull the switch, and straighten the pin (or replace switch) I hope you find the issue and get your board up and running.