QB Desktop Mac 2020 - How to extract invoice data with custom fields to CSV?

I own a music instrument repair shop and have used QB Desktop for Mac for many years for bookkeeping, managing parts inventory and creating / sending invoices. When I originally started using QB I set up the invoice template to use a couple of custom fields, particularly for instrument serial numbers. Because of this we were never able to move to QB Online or any other cloud-baed bookkeeping solution (they can't handle the custom fields that we require).

We are now in the process of implementing CRM software to handle invoicing and inventory (along with many other tasks) and will be free to move to a cloud-based accounting solution since we will no longer need to track data in custom fields (the CRM software will handle this moving forward).

I have around 10,000 invoices in QB Desktop Mac 2020 that I would like to extract the data from in to a CSV file. I've spent probably 20 hours so far trying to figure out how to do it and have failed miserably. I have been able to export a report of all transactions but the report does not include the critical custom fields I need. It's crucial to our business that we are able to look up the history of the instruments we've worked on so this is not helpful.

I have seen a couple of mentions of writing a script to extract the data however my meager programming abilities are probably not up to the task. There does not appear to be any third-party apps available to accomplish this either.

Does anyone have a solution for this? I'm not really looking to move the data in to the new software but I do need to have an archive of everything we've done to reference in the future.