It is more like an advanced way of using menus and has thousands of possible combination. Is it possible to add a feature where menu .nav items HTML can be changed using custom code.
For Example this is a themeable menu. Inserted an editbox inside the nav and it is also responsive in mobile breakpoints.
So is it possible to bring a feature which lets us edit the nav html with custom html code.
Sorry, this will not be possible. Each menu has a different structure and in many cases even changing one property will result in a complete different HTML output.
There is no way to make this work for every possible combination.