It can only control one set of monitor/hid but through the extension port you could wire up something for multiple computers power buttons (the ATX module menti

It can only control one set of monitor/hid but through the extension port you could wire up something for multiple computers power buttons (the ATX module mentioned by GP uses a rp2040, which has plenty of GPIOs). I think it would be simpler to buy a network PDU (or iot plugs) for your use case, assuming the computers can be set to power-on automatically.