Here's the default wallpaper from the 2019 Notebook 9 Pro and Notebook 9 Pen up for downloading if you'd like. Link also in the comments. I posted this before a while ago
Wallpaper Samsung Galaxy S10, abstract, 4K, OS #21189
Samsung Laptop Wallpapers on WallpaperDog
Get a taste of the Galaxy Book series with these official wallpapers - SamMobile