Unattended asynchronous file upload into SharePoint Online

Hello,

We have a need to share documents with an external partner.  We are thinking of doing this via external sharing through a SharePoint Online Document Library.  These documents are made available for a set time period for our client to download.  We have tried to use OneDrive to upload a document set into the library but sometimes with over a 100GB of files to upload it takes a very long time tying up a users machine (slows it right down).

Is there a way to select a set of files and then kick off some sort of 'batch job' (in the days of old) or asynchronous upload that can pick up files from say our server file share and upload these to SharePoint Online without user involvement and the user can just check a status report to see what has happened?  Essentially I need the user to be able to their machine without any performance issue and let a server call handle the upload.

Hope this makes sense. 

Thx.