This product will explain the usage of customfield generic (dynamic) child variant. The base product is ordable in this case.

Consider you sell products in different color settings: you want to change the color of the product by selecting a color variant.
Therefore dynamic child variants can be used to allow you different description, images, or product status for every variant of your base product.

Set up a new product, set price, add child products. Add created customfield generic child variant.
The child products are assigned to another unpublished category as the parent product for calculation or like in this case to no category.
Tick the checkboxes Display parent as option.