Create ACF field group and assign it to posts.
Create field label and name it color and choose field type Color picker.

Assign color to each post

Create a repeater in Oxygen builder

Select first child of Repeater
- Add class to that element “data-color-bg”
- Go to advanced > attributes > Add attribute. First field needs to be “data-color” and second one use data > Advanced Custom Field > Color


Add code block bellow repeater or for better experience use Scripts Organizer.
Paste JavaScript into JavaScript Tab
(function($){
    $(function() {
		$(".data-color-bg").css('background', function () {
			return $(this).data('color')
		});
		
    });
})(jQuery);Final result
