We also encountered this problem and did not find any alternative within Apple; in CFURLAccess.h, Apple recommends using NSURLConnection, but I could not find a way to perform the deletes with the specified class. It would seem that most third-party libraries also use CFURLDestroyResource.
Then we found the following: https://github.com/nkreipke/FTPManager . This FTPManager takes advantage of the fact that Objective-C is a strict superset of C and performs FTP operations, creating raw sockets and simply writing commands manually. This is a method that can be a little "nuts and bolts" for developers who are used to high-level solutions, but elegant in their minimalism and efficiency. And when you handle this, most other FTP frameworks probably still execute commands, such as at any level.