Point 1 - in configuration if the Custom Background if selected then give 2 option
Apply Color
Custom Background Image
If Apply Color is selected then provide a color pallet tool which allows for applying multiple color which can make a color gradient in background
If Custom Background Image is selected, then give an option to upload an image
Point 2 - in configuration, change the Auto Mode to Blur Background.
Point 3 - of the 4 option provided to select only one option can be turned on