[blop]

Wow! Thanks for that comment, I have a Dell U3818DW with a KVM switch and I didn't know you could control it with DDC commands!

So for linux (e.g. fedora):

  dnf install ddcutil
  ddcutil capabilities -d 1 # show the available commands
  ddcutil setvcp 60 0x11    # for example switch to HDMI 1
  # assign a global shortcut key to the `ddcutil setvcp` command you need

And for windows:

  - download the "Dell Display Manager" software from their support site
  - assign a shortcut key in the Dell Display Manager: "Input Manager" tab => "Favourite Input Shortcut Key"

I used the same shortcut (Ctrl-Alt-ScrollLock) for both linux(kde)/windows