I believe that the focus of the project is to block the default Bootstrap tags, but in some exceptions it is necessary to add custom elements like a 'nav' with other features. Therefore, it would be interesting to have an option in the settings that would allow the user to delete the native bootstrap classes.
Just overwrite them in your custom css. You can easily copy them from the default in the Styles pane using the menu on the right of each class. Copy it to your custom css file and alter away. No need to remove the defaults at all.
Yes, thank you for your response. But I can not move specific elements into the nav.
You need to be a more specific and give some more details on what you are trying to do for anyone to help you on this.