There is no easy way to apply wallpaper to every virtual desktop.
This utility takes care of that.
# Downloads binary from [releases](https://github.com/georgesofianosgr/wally/releases)
wget https://github.com/georgesofianosgr/wally/releases/download/v1.0.0/wally
mv wally /usr/local/bin
chmod +x /usr/local/bin/wally
wally image.jpg
You can also use MacOS quick actions to apply wallpaper from context menu (check releases notes)
This utility is still expirimental and
it updates the local sqlite db file "~/Library/Application Support/Dock/desktoppicture.db"
In case something goes wrong delete this file and MacOS will recreate it.
Code based on pywal wallpaper update.