@leocg I’m not sure if I was clear about this in the original post, but yes. The original (dark red, first picture) wallpaper was available. The issue is that when selected, what actually appears is the other one (white, second picture).
To simply restate: The issue is that although the dark theme is selected, a light one appears in its place.
See my previous post for more details, or ask me for any more you may need.