Indeed, I've recently had to use Google Drive API v3 and even though it's version 3 there's still a lot to improve.

Here's what you need to do to copy a file to different folder in C#:

            var newFile = drive.Files.Copy(null, fileId).Execute();
            var newFileInNewLocationreq = drive.Files.Update(null, newFile.Id);
            newFileInNewLocationreq.AddParents = newFolderId;
            newFileInNewLocationreq.RemoveParents = oldFolderId;
            var newFileInNewLocation = newFileInNewLocationreq.Execute();

To be fair it's just 2 API calls but rather verbose. And that's assuming all the calls work