ACF: Display Repeater Rows via Shortcode

<?php
add_shortcode( 'scseed_acf_repeater', function( $atts ) {
    if ( ! function_exists( 'have_rows' ) ) {
        return '';
    }

    $atts = shortcode_atts( [
        'field'   => '',
        'post_id' => null,
        'sub'     => 'item',
    ], $atts, 'scseed_acf_repeater' );

    if ( empty( $atts['field'] ) ) {
        return '';
    }

    $field_name = sanitize_key( $atts['field'] );
    $sub_name   = sanitize_key( $atts['sub'] );
    $post_id    = ! empty( $atts['post_id'] ) ? absint( $atts['post_id'] ) : null;

    if ( ! have_rows( $field_name, $post_id ) ) {
        return '';
    }

    $output = '<ul class="scseed-repeater-list">';
    while ( have_rows( $field_name, $post_id ) ) {
        the_row();
        $sub_value = get_sub_field( $sub_name );
        if ( $sub_value !== false && $sub_value !== null && $sub_value !== '' ) {
            $output .= '<li>' . wp_kses_post( (string) $sub_value ) . '</li>';
        }
    }
    $output .= '</ul>';

    return $output;
} );