In Odoo 18, how can I create a search or rolling report that lists all Invoices from the previous month with their line items and pull in fields like qty, price, and a few custome fields from Product?

In Sales -> Reporting -> Sales, I can see every Sales Order with the line items. I need the equivalent of this for Invoices. The use case is to then create a royalty report, which computes royalty owed based on items sold.

The ideal format is
IN 1   -  Product 1 - Qty - Price - customProductField1

In 2   - Product 2 - Qty - Price  - customProductField1

I have looked at Reporting --> Invoice Analysis and also a filtered search on Journal Entries. However, I am unsure about 2 main things:

1. How to pull in custom fields on the Product record for the products on the invoice
2. (Less important) How to make it a rolling report so that it updates every month