I'm a "clean install a LTS release every two years" kind of guy. I keep the default wallpaper because it's a reminder of what release I'm on. Kind of like a changing of the seasons type of thing.
The W11 SE laptop I bought this week had an energy drink ad as its default background. It was a genuine shock to see how bad things were getting over there in the Microsoft world.
I care so little about background that I just set it to black. But I just checked and at some point in the last few weeks or maybe even months it switched back to the standard one. Stange...