Graph API v5 upload file to sharepoint

I have installed the Graph API v5 using c# and I am trying to follow the below examples of uploading a file to sharepoint. Seems like some of the methods do not exist anymore in the graph API v5.

1st code doesnt recognise Items

var uploadSession = await graphClient.Drive.Items["itemId"].ItemWithPath("SWEBOK.pdf").CreateUploadSession().Request().PostAsync();

doesnt recognise Root

var uploadedFile = client.Me.Drive.Root  
                              .ItemWithPath("smallfile.txt")  
                              .Content  
                              .Request()  
                              .PutAsync<DriveItem>(fileStream)  
                              .Result;  

Graph API documentation

Upload example

Anyone can refer me to documentation of how to upload using graph api v5.

Is it better to use a older version of Graph API instead of the version 5. Also is it better to use http client call instead of using the SDK libraries. Thanks

If you know driveId then you can access MicrosoftGraphCreateUploadSession this way

var uploadSessionBody = new Microsoft.Graph.Drives.Item.Items.Item.MicrosoftGraphCreateUploadSession.CreateUploadSessionPostRequestBody
{
    // Item = ...
};
var uploadSession = await _client.Drives["driveId"]
                             .Items["itemId"]
                             .ItemWithPath("SWEBOK.pdf")                
                             .MicrosoftGraphCreateUploadSession
                             .PostAsync(uploadSessionBody);

Upload file to your Root

var uploadedFile = await _client.Drives["Me"].Root
                          .ItemWithPath("smallfile.txt")
                          .Content
                          .PutAsync(fileStream);

Doc:

Upgrade guide to v5