Show post publish date and last modified date together

function your_prefix_post_date( $output ) {
    $format        = apply_filters( 'astra_post_date_format', '' );
    $modified_date = esc_html( get_the_modified_date( $format ) );
    $modified_on   = sprintf(
        esc_html( '%s' ),
        $modified_date
    );
    $updated_output = '';
    $separator = ' /';
    $separator = apply_filters( 'astra_post_meta_separator', $separator );
    $published_string = _x('Published : ' , 'astra');
    $updated_string = _('' . $separator . ' Updated : ' , 'astra' );
    $updated_output       .= '';
    $updated_output       .= ' ' . $modified_on . '';
    $updated_output       .= '';
    $modified_output = $published_string . $output . $updated_string . $updated_output;
    return $modified_output;
}
add_filter( 'astra_post_date', 'your_prefix_post_date' );