Is it better, UX-wise, to list the design itself as the "main product"?

Well, as you say in your description, you are NOT selling the design as an illustration, that may well be digital, but rather the design applied to an object. Based on this, my logic tells me to see the design presented in a main object and then have the option to choose any other object with the applied design, but never the illustration alone.

Maybe you should have a look at teepublic to get ideas, since it is quite similar, if not the same, to what you describe in the question

Is it better, UX-wise, to list the design itself as the "main product"?

Well, as you say in your description, you are NOT selling the design as an illustration, that may well be digital, but rather the design applied to an object. Based on this, my logic tells me to see the design presented in a main object and then have the option to choose any other object with the applied design, but never the illustration alone.

Maybe you should have a look at teepublic to get ideas, since it is quite similar, if not the same, to what you describe in the question

Edit after the comment

I think the confusion lies in what is being sold as the main product: the design or the object.

• If it is the design, I think the relevant thing would be to show this design lied to a main product and the rest of the objects as secondary ones to choose from.

_Teepublic

• If it is the object (for example a garment), show a variety of applied designs, and colors, which would imply creating a clothing store, so, in my opinion, it would be necessary to limit the number of selectable products to avoid making it infinite.

_{Diesel store}