How to fix or identify monitor ID within a graphics card

I need help to identify the monitor-ID (DP-0, HDMI-1, etc) of a physical monitor port of the graphic card.
I am connecting basically four different type of monitor to single GeForce 1660, but sometimes remove some of them with power-on, or replaced by other types of monitors with same resolution and refresh rate.
In my old Fedora machine, the monitor IDs were persistent, and CONNECTED_MONITOR and custom EDID worked fine. However, after porting the system to Ubuntu 18.04, the monitor ID altered time to time.

Thank you very much in advance,