I manage files on my iPad (and iPhone) with Files and iCloud Drive. It’s been around for a while! The problem is that many apps are still stuck in 2015. But for apps that support it, using the Files file picker is no different than using the Mac file picker and Finder. You open files, you save them, they sync. Some apps do default to their own folder in iCloud Drive, but that folder can be accessed by any other app and is also available on the desktop.

Sadly third-party support for Files plugins is not what it should be (Google Drive is so incomplete I don’t know why they even bother). The major cloud services want you using their apps, I guess.

But Secure Shellfish does it perfectly so my Windows media server is available as a “file system” on my iPhone and iPad via SFTP.