ShareGate Migrate has these Microsoft file size limitations when copying your content.
Maximum upload size for a document in a library
SharePoint on-premises before SharePoint 2016: 2 gigabytes
SharePoint 2016: 10 gigabytes
SharePoint 2019: 15 gigabytes
Microsoft 365: 250 gigabytes
Note: The maximum upload size can be lowered or increased in your web application's settings for SharePoint on-premises. You cannot change that limit in Microsoft 365.
Maximum upload size for a list item attachment
SharePoint on-premises: 50 megabytes
Microsoft 365: 250 megabytes
Note: The maximum upload size for list item attachments can be modified for SharePoint on-premises. However, that limit cannot be changed for Microsoft 365.
In insane mode to an on-premises environment, ShareGate Migrate packages your content and sends it with attachments and metadata. The size limitation applies to the entire package instead of a single element.