That’s true.
That definitely depends on community norms.
What I’d be inclined to do is let people use whatever username they find appropriate, the real name in the name field, and a user_custom_field for their business name. You can configure it to display on their user profile and/or user card. That won’t show it on every post, though a theme component count conceivably add it.
But if your system is working then it’s working. You could customize text to make the labels for the name field be “business name” or similar.