This is not a bug. This a wishlist thing that I was told to make here when I asked for this feature on lemmy. There is no option in the settings to span a wallpaper across both monitors. There is only one app (superpaper) and it hardly works normal on xorg, and doesn't work at all on wayland (my main). I would love to have this as an option in settings. Thank you
*** This bug has been marked as a duplicate of bug 393781 ***