// Getters & Setters, конструкторы, валидация и документация опущены
public class CreateProductRequest {
    private String name;
    private Double price;
}
public class ProductResponse {
    private Long id;
    private String name;
    private Double price;
}
@PostMapping("/products")
public ResponseEntity<ProductResponse> createProduct(
    @RequestBody CreateProductRequest request
) { /*...*/ }

public enum ProductDTO {;
    private interface Id { @Positive Long getId(); }
    private interface Name { @NotBlank String getName(); }
    private interface Price { @Positive Double getPrice(); }
    private interface Cost { @Positive Double getCost(); }
    public enum Request{;
        @Value public static class Create implements Name, Price, Cost {
            String name;
            Double price;
            Double cost;
        }
    }
    public enum Response{;
        @Value public static class Public implements Id, Name, Price {
            Long id;
            String name;
            Double price;
        }
        @Value public static class Private implements Id, Name, Price, Cost {
            Long id;
            String name;
            Double price;
            Double cost;
        }
    }
}

@Value public static class PatchPrice implements Id, Price {
    String id;    // Должен быть тип Long;
    Double prise; // Опечатка в слове price
}

PatchPrice is not abstract and does not override abstract method getId() in Id
PatchPrice is not abstract and does not override abstract method getPrice() in Price

private interface Cost {
    /**
     * The amount that it costs us to purchase this product
     * For the amount we sell a product for, see the {@link Price Price} parameter.
     * <b>This data is confidential</b>
     */
    @Positive Double getCost();
}

markup = (sale_price - cost_price) / cost_price

public static <T extends Price & Cost> Double getMarkup(T dto){
    return (dto.getPrice() - dto.getCost()) / dto.getCost();
}