It's hard to draw complete conclusions from your pictures. It looks like you damaged the receiving socket end of the ZIF connector. With these connectors, I actually believe it would work the way it is right now. I am not 100% positive you have it fully inserted based on the pictures. Can you upload pictures with it disconnected?
For the external, are you using a USB Hub to then plug in a USB A keyboard? Often times hubs need permission granted to be functional. Try using a direct USB C keyboard.
My biggest concern here would be if at any time you disconnected anything on the logic board with the computer still on. If you did that, then yes your keyboard is almost certainly fried.