I run Arq Backup automatically in the background.
It copy Photos, iCloud files and my mails once every days to S3 with incremental backups.
It requires to have a full copy locally.
Works great!
It is not hard to configure once, with the proper folders and settings.
> It requires to have a full copy locally.
yeah that's the thing. When my iPhotos library exceeded 1TB I lost the ability to store the full local copies. Since then, iCloud itself has been the sole source.
Looks like there's some decent, reasonably priced apps to handle this like https://apps.apple.com/us/app/parachute-backup/id6748614170?... (no affiliation)