I'm sorry you're frustrated at this moment. Please allow me to explain one more time:
You can still use what are now referred to as "Classic Elements" both within Cornerstone and in the WordPress admin. However, you can only use the legacy shortcode generator in the WordPress admin and not within the drag-and-drop interface of the content builder.
In the WordPress admin you can still utilize the legacy shortcode generator, which is now turned off by default as we strongly encourage users to utilize Cornerstone's visual interface. To enable the legacy shortcode generator, go to Pro → Seettings in the WordPress admin, and towards the bottom of that page you will see this option:
Checking that box will bring back the shortcode generator in the WordPress backend, seen here:
In the drag-and-drop builder, you cannot utilize the shortcode generator anymore (for example, with a "Text Element"), because of various reasons, mostly to do with performance and our new systems that aid with the generation of markup, dynamic styling, et cetera. That being said, it doesn't seem as though you are interested in utilizing the drag-and-drop portion of Cornerstone, so you should be all good to go here.
Hopefully this helps to set you on the right path.