I need to count the files created by the requesting user in a shared drive. I understand that there is no real ownership concept for files in shared drives. But when viewing the details of a file on the Drive Webapp it shows a field named "Creator", even in shared drives. So this information must be stored anywhere. It is possible to query it somehow through the Drive API?
Currently there is no method to return the creator in Google Drive API at the moment.
This is a product limitation for Google Drive API, this request can be promoted for future development through here.
As an alternative, you can get the creator of a Shared Drive by using the Google Drive audits from the Reports API https://developers.google.com/admin-sdk/reports/v1/appendix/activity/drive#create, however, data retention time for reports is 6 months.