It almost seems like a rite of passage, connecting to a projector after ditching the floating WM.
While it may seem hard, it’s actually quite easy!
View connected video outputs
eDP1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 310mm x 170mm
HDMI1 connected (normal left inverted right x axis y axis)
Select one of the available video outputs, e.g.
> xrandr --output HDMI1 --auto