I just wanted to share a quick tip I use.
I often see people use Zapier or miniExtensions to do this basic operation so it may be easier to do this way.
I am using the Automation feature of Airtable to trigger when the record has a “pending URL” (that should be processed).
When triggered, Airtable let’s you set the Attachment field type with an “URL” value and will automatically convert it. (tested for images and PDFs)