Error trying to POST an attachment using API

The field in question is an Attachment field.

This is what my POST looks like (from Power Automate Desktop. Note variables are enclosed in %s). The field in question is highlighted

I receive this error

{"error":{"type":"INVALID_ATTACHMENT_OBJECT","message":"Invalid attachment object for field Lawsuit Docs - PDF: \\"https://drive.google.com/file/d/1Y_4OYYb7NjIKremnh3aiuFFEh6smESFK/view?usp=drivesdk\""}}

TIA