Display reports based off date_completed, not date_created

I understand that when WooCommerce Admin syncs order data for reports, it uses the WC_Order::get_date_created() method. We run a WooCommerce store that only allows for online order pickup and the customer pays when they pick up their order. For accounting purposes, I need to display our reports based on the date the order is completed, not created. Can I modify the code to WC_Order::get_date_completed() to accomplish this? I understand if I hardcode the change, it would not survive a plugin update. That is OK as this is just a temporary solution to get us through the end of the year.

If not, could you point me in the right direction?

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