Keyboard not working but everything else is working fine.

This is more than likely the cause of your keyboard issue. This little board here is responsible for keyboard and trackpad functions, both of which are transmitted to the logic board itself via the cable you see that curls into the hole here and connects to the underside of the trackpad.

The big wide flex cable to the right of it is for the keyboard itself. An the skinnier flex cable to the left which is creeping out from under the logic board is for keyboard backlight. Both of those functions are handled by this small board. It’s a fairly common fault due to the trackpad’s limited protection from liquid entry. That small board can be replaced independently of the rest of the top case, but it’s a little tricky to source. My usual parts go to stocks it, but they only sell to businesses, not end users so depending on your situation and location they may not be an ideal place to get it.