No, that's not how it is.

I then use that product to hand it off to the construction crew. Without that design, they wouldn't know what to build.

No, that's not how it is. I'm not paying someone to design me a part. For example, I want to build a summer cottage. I hire an architecture agency to produce the blueprint of the house. That blueprint is a finished product, a complete product (not a part of the product) that the agency delivers and I am happy to pay for it.

I then use that product to hand it off to the construction crew. Without that design, they wouldn't know what to build.