My desk has two monitors that I want to have extended to each other. I also have a TV in another part of my room. On KDE and Windows, there are settings that allow the TV to mirror one of my displays from my desk, so I can play games or watch media on my couch without the need for a console or secondary HTPC. This configuration works much better than just having the TV as another extended display.
In the Zorin App Menu, there is a dedicated button for Settings
Click that and then in the left pane, scroll down to Display
There you will see options to join display, mirror displays, etc.
Yes I understand, but that display menu is not capable of (for example) having Display 1 & 2 extend to each other side-by-side and in the same configuration have Display 3 be a mirror of Display 2.
I made a similar post on r/GNOME and someone said I needed to download this thing called ‘gnome-monitor-config’ which from what I’m seeing is a small and unmaintained GitHub project from 2019.
I do not use Gnome... So I am unable to test this.
Otherwise, I believe Gnome sets the configuration in ~/.config/monitors.xml
This can be manually modified and configured. Since I use Zorin OS Lite (XFCE instead of Gnome), mine is in ~/.config/xfce4/xfconf/xfce-perchannel-xml/displays.xml
In this file, for the monitor in question, you can set whether mirrored: