The keyboard connected to the PS/2 port on the back of the case doesn't work. However, I can still hear a faint beeping sound from the BIOS speaker when pressing individual keys. The keyboard starts working when I bend the port (or maybe a piece of the PCB). I decided to desolder the port and replace it with a new one. While desoldering, I tore out a trace – pin 5 in the photo. This is the "clock" for the keyboard port.

Once I solder the new port and repair the trace, I'll see if it was actually physical damage. However, I recently started having doubts.
The USB keyboard/mouse on this motherboard didn't work from the start. I was hoping this was normal for this model (it's rare, but I've encountered such boards before). Furthermore, after Windows loaded, the USB port correctly detected the flash drive, although only one of the two did. Out of curiosity, I connected the external USB ports to the motherboard's connector and the keyboard to it. And it turned out the keyboard worked in the BIOS.
Furthermore, I noticed that the rear ports no longer detected the flash drive. Both fuses near the ports are working.

I'm writing about these two things because I have a feeling they have something in common. On the other hand, it could be a coincidence. Could a failure of some discrete component on the PCB near the USB ports cause such strange behavior? I read a thread about removing an SMD component that caused PS/2 to start working on Asus motherboards. But I don't want to remove it until I understand its exact purpose. I'm talking about a component with 8 pins.