How to output Custom Fields with functions.php

Hello,

I am new to Metabox.io and I am looking for a way to output custom fields to a Single product page (WooCommerce) below the short description text.

I know how to output the custom field I created with Metabox.io directly in the template pages using:
<?php $value = rwmb_meta( 'my_custom_field' ) ?>
<p>Here comes the custom field: <?= $value ?></p>

But is there a way to add a function in functions.php to output the custom field with the hook "woocommerce_before_add_to_cart_quantity"?

By the way… I am using a Block Theme (Gutenberg).

Thanks for help,
Michael