I really appreciate that in linux anything can be scripted, including setting the wallpaper. So everytime I disconnect a monitor I can just rerun my script and fix my wallpaper without digging deep into the ui and fussing through a bunch of settings.

feh --bg-scale ~/.config/awesome/wallpaper/my_wallpaper.png

I set my default wallpaper with feh using the command above.

Leaning in on feh, we can use fzf to pick a wallpaper from a directory full of wallpapers with very few keystrokes.

alias wallpaper='ls ~/.config/awesome/wallpaper | fzf --preview="feh --bg-scale ~/.config/awesome/wallpaper/{}" | xargs -I {} feh --bg-scale ~/.config/awesome/wallpaper/{}'

I have mine alias'd to wallpaper so that I can quickly run it from my terminal.