When it comes to wallpapers, you could do a similar trick on X11 DEs by putting it onto the root window (with a tool like xwinwrap) and on Wayland DEs that support layer-shell (with a tool like windowtolayer). I'm not aware of screen lockers that do something like that, but you could always write your own one.
Plasma wallpaper plugins are, well, for Plasma.
When it comes to wallpapers, you could do a similar trick on X11 DEs by putting it onto the root window (with a tool like xwinwrap) and on Wayland DEs that support layer-shell (with a tool like windowtolayer). I'm not aware of screen lockers that do something like that, but you could always write your own one.