For on premises versions prior to 2016 the file size limitation comes from SharePoint. It imposes a maximum file size of 2 gigabytes per file.
For SharePoint 2016, the maximum file size has been increased to 10 gigabytes.
For Office 365, the maximum file size has been increased to 15 gigabytes.
For SharePoint 2016 you need to manually edit the web application where your site collection resides.
There is a setting that limits the size of file you can upload, and by default the size is much less than 10 gigabytes. You can manually upload the files to SharePoint with your browser, and then use ShareGate Desktop's Bulk Metadata Editor feature in order to manually set the field's values.