[rowanG077]

How is Serial mouse/keyboard trivial? You'd need to make a custom mouse that receives data from your second PC. You'd probably want it to be wireless else you will have 2 cables coming out of it. And no just having a second fake mouse is not fair. That's easily detectable by software and would definitely raise a lot of red flags.

[xxs]

This is how: take ESP32 - it has bluetooth, wifi and serial port all integrated and it costs couple of dollars. It's small and it runs on 3.3V, it has a voltage regulator that it allows to connect to 5V.

I can do the code and place the esp32 in a mouse on a Saturday (my C is always rusty, not using it professionally). And I am a hobbyist at best. So the original serial mouse/keyboard are connected to ESP32 that normally proxies the signal of the hand movement to the PC.

If I press a pedal (w/ foot) the second computer would receive a signal, calculate a human alike trajectory to move the mouse and send it to the ES32. The latter will execute it along with the left click to shoot.

Like I said - trivial. The same can be done with the USB port as well, and it's not harder. Just that for PS/2 I have the tools laying around.

[seba_dos1]

It is trivial. All you need is a device that can work as a USB gadget that you can plug your keyboard into. I could do it with my phone, many Raspberry Pi-like SBCs, or even Arduino-like boards...