Good morning,@David Musgrave, has some great suggestions (as usual :) ). We had similar requirements, and we also transmit ACH files, so had security concerns with sensitive account information being stored in text files accumulating in directories that all the accounting staff had access to.
If you're using Office 365 and have access to Power Automate, we chose to implement a Power Automate flow that waits for a file to be generated, and as soon as it's generated (usually it's in the folder less than 30 seconds), it sends it to the bank via a secure FTP (SFTP), then removes the file from the GP shared directory, and places a copy (for backup) in a secure SharePoint folder where the general accounting staff does not have access. As David mentions, you can protect the file in a multitude of ways, we use a re-naming strategy that makes it easier to archive and locate at a later date. It had the added benefit of saving time by manually uploading files, and having less of a need to share bank login credentials. If you change banks, Power Automate is also a quick switch to change out a connector with the new bank credentials and/or transmission method, which may be simpler than a coded solution.
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