This worked for me.
In the XFCE display settings in dom0, set up the displays as you want them to be and save the profile.
In the same tab where you manage the profiles, you can toggle a switch that automatically enables profiles when displays are connected.
I have 3 displays connected, one is connected to a KVM, I only had to make a profile for the setup with 3 displays connected, I never had any issues with disconnecting a display.