Well it's not as if people are paying for GNOME.
Is there something on the issue tracker to add it back?
Rather than creating some drama or calling out a GNOME developer, why not see if you can implement the feature?
The odds are they'd welcome the contribution.
Edit:
Looks like it's not part of the "design vision" of GNOME.
However gotta say there seems to be a lot of hostility generated.
https://gitlab.gnome.org/GNOME/gnome-control-center/-/issues...
The ability to change the background is apparently still available via cli:
$ gsettings set org.gnome.desktop.background picture-uri ''
$ gsettings set org.gnome.desktop.background primary-color '#123456'