How to determine the root cause of the error that occurs while creating documentset using /_vti_bin/listdata.svc endpoint in SharePointOnline?

Question

While trying to create a DocumentSet with a name that already exists in DocumentLibrary using /_vti_bin/listdata.svc (SPO) a 500 internal server exception is thrown. I understand the reason for the exception, but 500 internal error can be thrown for various reasons, and i couldn't from the error response infer the cause of the error. The API call is made from .net application (HttpClient), the response content is as below:

{
"error": {
"code": "", "message": {
"lang": "en-US", "value": "An error occurred while processing this request."
}
}
}

I have two questions:

1. How to get detailed error information from call to listdata.svc, so that appropriate logic can be executed if error is due to DocumentSet already existing?
2. Is it possible to structure the call so that a DocumentSet is created if it does not exists?

Note: Checking if a DocmentSet exist prior to making call to listdata.svc is not an option due to multiple calls/race conditions.