How to upload multiple images to use as gallery in Kirki Framework

Question

I am using Kirki Option framework which works like charm in most cases, I recently shifted from Redux framework. I have a section in my website for the gallery, I want to upload multiple images using Kirki 'image' control where I want to save those images ID. I have custom image size for the thumbnail which is defined in functions.php file:

add_image_size('home-gallery-thumb', 400, 300, true);

and this is what I am using to create a field in customizer:

Kirki::add_field( 'my_gallery', [
        'type'      => 'image',
        'settings'    => 'my_gallery_st',
        'label'       => esc_html__( 'Gallery Images', 'txtdom' ),
        'description' => esc_html__( 'Upload Images for the gallery section', 'txtdom' ),
        'section'     => 'my_gallery_sc',
        'choices'   => [
            'save_as'   => 'id',
        ],
    ]
);

In the output I want to display thumbnail using wp_get_attachment_image_src() function for the specific image ID and when user clicks the image the full image will display in lightbox.

But the problem is using this control I can only upload one image. I don't know what I am missing out. I did research in google for the issue and found that the multiple image upload feature is implemented from Kirki 3.1 version but I don't find anything to use it in their documentation. Can anyone help me do this?

Thanks in advance.