In order to share information between Convertkit and your Gravity form, you MUST create a ConvertKit FORM and connect your Gravity form to it. So you are stuck with all the limitations of a Convertkit form. You cannot connect your Gravity form directly to a field in your Convertkit database. This makes no sense at all. Do not use Gravity forms if you are trying to improve the information that feeds into your Convertkit database.

You have to manually map your Gravity form to the Convertkit form. It does not automatically populate the Gravity form with available fields from your Convertkit database.

You can create better fields/questions in Gravity that are not connected to Convertkit and collect information that you can manually move over to Convertkit, but what is the point?