Retrieving a JSON object key with jsonPath

Hello Experts,

My input contains 2 headers. In one header, the value is in JSON format.

I am trying to write it in a CSV file but as this is in array format, I am getting below error:

I tried using .toString(), but then it negates all the quotes.
I want JSON format to be intact. Below is the format in which I want CSV to be created:

Thanks in Advance