Hi David, thank you for your question!
The easiest way to import large backups into Cloud WordPress websites is to use the Download Link option in the backup upload tools.
You can generate a download link in your original website using Total Upkeep which you can then use in your Cloud WordPress installation to transfer the files. We also have a guide in our support center that demonstrates how to migrate website content that I think you will find useful as a reference.
I hope that helps you get your backup moved over and please let us know if you have any additional questions!