How are customers migrating thousands of Leases with attachments?

Summary:

Data migration with attachments?

Content (please ensure you mask any confidential information):

I cannot see an option to upload attachments via the FBDI, and I cannot find a REST API to support the upload of attachments.

How are other customers with large volumes of leases adding attachments?

Version (include the version you are using, if applicable):

24B

Code Snippet (add any code snippets that support your topic, if applicable):