Numbering scheme with product attribute

I am looking for a way to integrate an attribute into the numbering scheme for documents. The attribute is assigned to a product (project number). Each project number is unique and is entered into the corresponding field when the product is created. Each product should have its own generated 5-digit number.

Finally, the filenames and numbers should look as follows:

435698-10065 (Project number-generated number)

Can someone tell me how I can access the product's attribute in the project initialization rule?

Greetings,
Joshua