SharePoint - Timeout Error - Copying Folder To Another Folder - sharepoint-online

Question

When I call this method enough times, I think I'm getting throttled because I'm seeing a connection timeout (instead of a 429).
I have a large set of files in a folder that I'm looking to copy to another folder, and looking for suggestions.
Thanks!
public void AddNewFileAndCheckIn(string sharepointFolderRelativeURL, string localFilePath, string indexName)
{
try
{
// Get the Folder
//Folder fileFolder = Web.GetFolderByServerRelativeUrl(this.GetFolderRelativeUrl(sharepointFolderPath));
var initTimeout = ClientContext.RequestTimeout;
var timespans = new List<TimeSpan>();
timespans.Add(TimeSpan.FromSeconds(300));
timespans.Add(TimeSpan.FromSeconds(300));
Polly.Retry.RetryPolicy policy = Polly.Policy.Handle<Exception>().WaitAndRetry(timespans);
policy.Execute(() => {
using (var reader = new System.IO.StreamReader(localFilePath))
{
Folder fileFolder = Web.GetFolderByServerRelativeUrl(sharepointFolderRelativeURL);
// Add the File
FileCreationInformation fci = new FileCreationInformation();
fci.ContentStream = reader.BaseStream; // System.IO.File.ReadAllBytes(localFilePath);
fci.Url = System.IO.Path.GetFileName(localFilePath);
fileFolder.Files.Add(fci);
ClientContext.Load(fileFolder);
ClientContext.RequestTimeout = initTimeout * 10;
ClientContext.ExecuteQuery();
// Get the newly checked in (added) SP File
File fileToCheck = Web.GetFileByServerRelativeUrl(System.IO.Path.Combine(fileFolder.ServerRelativeUrl, fci.Url));
ClientContext.Load(fileToCheck, item => item, item => item.ListItemAllFields["Created"], item => item.ListItemAllFields["Modified"]);
ClientContext.ExecuteQuery();
// Update Metadata
fileToCheck.ListItemAllFields["Created"] = new System.IO.FileInfo(localFilePath).CreationTime;
fileToCheck.ListItemAllFields["Modified"] = new System.IO.FileInfo(localFilePath).LastWriteTime;
fileToCheck.ListItemAllFields["Index"] = indexName;
fileToCheck.ListItemAllFields.Update();
ClientContext.ExecuteQuery();
}
});
}
catch (WebException wex)
{
throw new SharepointOnlineException(string.Format("Exception In AddNewFileAndCheckIn('{0}','{1}', '{2}')", sharepointFolderRelativeURL, localFilePath, indexName), wex);
}
catch (Exception ex)
{
// Catch and Rethrow with Details
//throw new SharepointOnlineException(string.Format("Exception In AddNewFileAndCheckIn('{0}','{1}', '{2}')", sharepointFolderPath, localFilePath, indexName), ex);
throw new SharepointOnlineException(string.Format("Exception In AddNewFileAndCheckIn('{0}','{1}', '{2}')", sharepointFolderRelativeURL, localFilePath, indexName), ex);
}
}