Hi Sergio.
First, thank you for the great review.
Now, to your question.
As we stated in the article, we can use both the required keyword and the null! statement to mark our properties as not null when working with EF Core.
However, the required keyword is preferred because it forces us to assign a value to a required property during instantiation. If we try to create an instance of our model without assigning a value to our required property, it will raise an exception.
In contrast, the null! statement doesn’t do this. With the null! statement, we can leave our property without a value during instantiation, and we won’t get any warnings or exceptions.