I've not heard of any plans to deprecate these, but you never know.. I assume any such deprecation would have a long warning to allow people to switch over.
That said, they aren't recommended to use either:
https://experienceleague.adobe.com/en/docs/analytics/export/analytics-data-feed/create-feed#legacy-d...
If you can use the recommended options, I would go with those... but if you can't, and you have to use something like FTP or SFTP you may have to go that route.