The built-in wallpaper selection app of Chromebooks has a “Surprise Me” option, which would set a random wallpaper on every boot.
How to change the default desktop wallpaper on Chromebooks and other ChromeOS devices like Chromebase?
How to enable Caps Lock on Chromebooks, as there is no dedicated Caps Lock button on Chromebook keyboard? Learn the keyboard shortcut.
If you are facing any critical issue with your Chromebook or other ChromeOS devices, the easiest way to fix it is powerwashing the device. Powerwash resets Chromebook to be just like the new, and hence should fix most of issues related with the user account and settings.