To improve the UI I suggest do improve how subquestion codes for the exclusive option feature get added. Currently this is a free text field. Any typo when entering the exclusive option leads to problems.
Instead, let's make it a multi select similar to the feature of adding additional survey languages. That allows searching and picking multiple items. We can limit the available options to the subquestions of the given question. That way the user can pick the relevant option(s) froma predefined list.