This might sound super unimportantant but hear me out. One of the first things we’re taught in design is to avoid tangents unless in super rare cases because they create tension/they’re not pleasing to look at. The X on the backgrounds is a tangent. I don’t know if it’ll change with Gnome 42 but it’d look a lot better if it was moved away from that corner.
edit: Right click on desktop, select change background. It’s the panel that lets you select the background.