What I'm trying to achieve is to add new args ( output ) as below:
$wp_customize->add_setting( 'modular_header_main_border_bottom_color', array( 'default' => '#e9ecef', 'capability' => 'edit_theme_options', 'output' => array( array( 'element' => 'body', 'property' => 'background-color', ), ), ) );
And, get output array in front and enqueue it as a valid CSS. Till now, I've tried achieve the same using customize_dynamic_setting_args hook which works fine in Customizer. But the problem is data from it is not accessible in frontend. https://pastebin.com/AEdmPJDV
I guess there should be another way of doing same.