Attachement unfound in sftp - Attachfile()

We want to send attachments to clients as soon as they arrive on the SFTP using AttachFile.Here’s what we’ve tried so far:

• Using legacy APIs to list filenames in the SFTP directory → but itonly fetches the first 50 files, no more.

• Re-sending the email every hour when the client hasn’t received it →but as soon as the attachment lands, the client ends up receiving theemail multiple times (as if all previous attempts were stuck andreleased at once).

• Relying on Marketing Cloud to resend the attachment automatically,like it did in the previous setup — but I’m not entirely sure howthat behavior worked, or if it can be replicated.

Do you know if there’s a reliable solution.

Thanks a lot in advance.