Use DDC/CI to control the monitor inputs

[timgws]

Use DDC/CI to control the monitor inputs, so a hardware matrix is not required.

[timgws]

Each OS has different APIs to communicate with the monitor.

ddcctl (https://github.com/kfix/ddcctl) has a nice command line util for macOS.
ddccontrol (https://github.com/ddccontrol/ddccontrol) works for Linux.

I have no idea what APIs to hit for Windows. As an aside, For macOS, I really like the MonitorControl UI. It allows you to override the brightness keys on your keyboard to control the monitor's brightness so that third-party monitors work exactly like Apple Displays.

[AJolly]

If thats what you want you can use https://github.com/fiddyschmitt/SimpleKVM