One possibility is creating large RAPs of your Pega data efficiently and without affecting production users, for example by first copying data to a different database. Generated RAPs can then be pushed to the Cloud vendor's way of doing file storage.

A "google" query for  "aws large file" upload" shows what Amazon Web Services (AWS) would recommend.

According to this web page: https://www.jtouzi.net/uploading-a-large-file-to-amazon-web-services-s3/ you can upload up to 5TB using AWS's Multipart Upload API.

A very fast network connection is a must obviously.

Google has this option: https://cloud.google.com/solutions/transferring-big-data-sets-to-gcp

Azure seems more complex. Found this: https://stackoverflow.com/questions/22829854/how-to-upload-files-to-a-windows-azure-storage. 

Any Cloud vendor would gladly assist, I am sure.

For database data migration, as opposed to files, Amazon offers this: https://aws.amazon.com/dms/

Has the ability to transfer petabytes as would be found in a data warehouse.

The piece still missing is how to transfer Decisioning Interaction History (IH).

I have been told AWS offers a Schema Conversion Tool (CST) plus a "Data Mover".  I do not know if this specifically refers to Teradata's Data Mover.

AWS's main data migration page: https://aws.amazon.com/cloud-data-migration/