It might help to review https://www.odoo.com/documentation/functional/accounting.html

The cost of any asset you ship, whether it be raw materials or finished goods, flows through the stock interim delivered account to COGS.

If you use a raw materials asset to manufacture a finished product asset, the shipping costs of receiving those raw materials will only become part of COGS if you inject them into the cost of the raw material asset via a Landed Cost adjustment BEFORE you start transforming it into a finished product.

Also review:

https://www.odoo.com/documentation/user/13.0/inventory/management/reporting/integrating_landed_costs.html

https://www.odoo.com/forum/help-1/question/what-is-landed-cost-with-real-time-evaluation-129717

I am unclear by what you mean by "accounting for the shipping cost of obtaining the raw materials" if it is not by recording a landed cost adjustment.

The debit account on the Vendor Bill for shipping costs and the credit account used on the Landed Cost adjustment are determined by the accounts chosen as the stock input account on the Product Category that the landed cost service belongs to.