[arthurfm]

One of the easiest ways to do this is to use a HDMI display emulator [0]. Set the resolution to 1920x1080, move the content or presentation you want to share to the 'ghost' monitor and then share the entire second screen in your meeting app [1].

[0] https://www.amazon.co.uk/s?k=display+emulator

[1] https://youtu.be/RA-XXvFHgEs

[ithkuil]

I honestly don't know if I want to be delighted or horrified by the need of a physical hack to trick your OS that there is a virtual monitor to share