PHP coding required - Wordpress/Woocommerce

Description

We have upgraded our server to PHP ver 8.0 and also a plugin and some custom code in the functions.php needs re-writing.
The code pulls in the 'delivery date' date from the woocommerce order via a plugin called 'Extra Product Options & Add-Ons for WooCommerce'
There is also some custom code used for our export order plugin for our csv file, where it ads the delivery date to the csv file. It also adds a notes field to the csv file.
I can demo the issue on Zoom and show you the existing code.
I estimate 2-3 hours job