Bootstrap 4 Carosuel with ACF Repeater field

Did you check the Advanced Custom Fields documentation? You can check how the repeater fields work here: https://www.advancedcustomfields.com/resources/repeater/

You’ll see that you can do the following to show your ACF repeater images on the front-end:

if ( have_rows('carousel_repeater') ) : 

    while ( have_rows('carousel_repeater') ) : the_row();

        $yourImage = get_sub_field('carosuel_image');
        
        if ( $yourImage ) : 

            echo wp_get_attachment_image( $yourImage, 'full' );

        endif;

    endwhile;

endif;

Above snippet assumes that your Image Field is set to ID. If your Image Field has another return type, see https://www.advancedcustomfields.com/resources/image/.