The Refinitiv Data Platform APIs are based on JSON as one of the most popular open standard file / data exchange formats.
If you want to convert CSV or other formats you can do so using other 3rd party / open source libraries - for example on Python the pandas library has functionality to convert a json file to csv file. It should also be possible to do the same in other languages.
Hi @alejandro.lesaga, as Umer has pointed out, all the response data from RDP is based on JSON format only.
The ESG data is also available in the bulk download format, and I believe it is provided as a CSV file. The API for that is Client File Store which is currently in Beta, and needs a separate set of entitlements. Although, there is no ESG example, you can read about the CFS API in this tutorial. For bulk ESG data, the bucket name is EDS-BULK-ESG-Production.