You can use discover or just use KDE Store or pling and have ocs-url installed so you can hit the install button and it will put it in the right spot. Since the store an pling are where they are pulled from.
If you have wallpaper engine its what i use personally Share your desktop! - #433 by EliteAMDGamer but you cant really make your own wallpapers on linux you kinda can with proton but its a pain. So i still have smart video wallpaper as a backup.