Trying to add a custom button in woocomerce in checkout via plugin

I´m trying to create a plugin to add a custom button in the woocomerce checkout just before clicking on place order, but no matter what I do it never shows up on the page.

function add_custom_button_before_place_order() {
    ?>
    <div style="margin-bottom: 20px;">
        <button type="button" class="button alt" id="customButton">My Custom Button</button>
    </div>
    <script type="text/javascript">
        document.getElementById("customButton").onclick = function() {
            alert("Button clicked!");
        }
    </script>
    <?php
}

add_action('woocommerce_review_order_before_submit', 'add_custom_button_before_place_order');

Thank you so much.